The war games were unprecedented, taking place close to Ukraine's border and involving thousands of troops, tanks and fighter jets. Russia had flexed its military muscles and triggered outrage across the world.
The crisis in east Europe began with civil unrest leading to the ousting in February of the then Ukrainian President, Viktor Yanukovych – before escalating with the Russian annexation of Crimea, in March, and the beginning of an "anti-terror" campaign by Ukrainian forces against pro-Russian separatists in April. As clashes continued to build with the passing months, accusations of Russian troop involvement in east Ukraine's bloody conflict became increasingly vehement.
Then, as pro-Russian rebels won a series of victories against government forces in Donetsk and Luhansk, what had begun as suspicions of Russian military involvement – the "green men" referred to in Crimea – became outright accusations of up to 10,000 soldiers sent across the border.
This week, as world leaders met in Wales with the Ukraine crisis high on the agenda, it emerged that Russian defence spending had been rising at an unprecedented rate. Moscow's defence budget is due to be double that of France within two years, and has risen by 18 per cent each year in the past three years.
But the spending is not described as a "knee-jerk reaction" to the Ukraine crisis. "This is a long-term government policy and a political priority for Moscow," said Craig Caffrey, the senior defence budgets analyst at IHS Jane's.
Observers say that to understand the increased military spending, and resulting aggression on the world stage, the key is to understand the final two decades of the Soviet Union, when Vladimir Putin "watched the Soviet descent to oblivion begin, accelerate, and then end in a humiliating wreck", The Washington Post reported.
Ukraine crisis: A timeline of the conflict
Ukraine crisis: A timeline of the conflict
1/22 30 November 2013
Public support grows for the “Euromaidan” anti-government protesters in Kiev demonstrating against Yanukovych’s refusal to sign the EU Association Agreement as images of them injured by police crackdown spread.
2/22 20 February 2014
Kiev sees its worst day of violence for almost 70 years as at least 88 people are killed in 48 hours, with uniformed snipers shooting at protesters from rooftops.
3/22 22 February 2014
Yanukovych flees the country after protest leaders and politicians agree to form a new government and hold elections. The imprisoned former Prime Minister, Yulia Tymoshenko, is freed from prison and protesters take control of Presidential administration buildings, including Mr Yanukovych's residence.
Genya Savilov/AFP/Getty Imageses
4/22 27 February 2014
Pro-Russian militias seize government buildings in Crimea and the new Ukrainian government vows to prevent the country breaking up as the Crimean Parliament sets a referendum on secession from Ukraine in May.
Sean Gallup/Getty Images
5/22 16 March 2014
Crimea votes overwhelmingly to secede from Ukraine and join Russia in a ballot condemned by the US and Europe as illegal. Russian troops had moved into the peninsula weeks before after pro-Russian separatists occupied buildings.
6/22 6 April 2014
Pro-Russian rebels seize government buildings in the eastern cities of Donetsk, Luhansk and Kharkiv, calling for a referendum on independence and claiming independent republic. Ukraine authorities regain control of Kharkiv buildings on 8 April after launching an “anti-terror operation” but the rest remain out of their control.
7/22 7 June 2014
Petro Poroshenko is sworn in as Ukraine's president, calling on separatists to lay down their arms and end the fighting and later orders the creation of humanitarian corridors, since violated, to allow civilians to flee war zones.
8/22 27 June 2014
The EU signs an association agreement with Ukraine, along with Georgia and Moldova, eight months after protests over the abandonment of the deal sparked the crisis.
LOUISA GOULIAMAKI/AFP/Getty Images
9/22 17 July 2014
Malaysian Airlines flight MH17 is shot down over eastern Ukraine, killing all 298 people on board. Ukrainian intelligence officials claim it was hit by rebels using a Buk surface-to-air launcher in an apparent accident.
10/22 22 August 2014
A Russian aid convoy of more than 100 lorries enters eastern Ukraine and makes drop in rebel-controlled Luhansk without Government permission, sparking allegations of a “direct violation of international law”.
11/22 29 August 2014
Nato releases satellite images appearing to show Russian soldiers, artillery and armoured vehicles engaged in military operations in eastern Ukraine.
12/22 8 September 2014
Russia warns that it could block flights through its airspace if the EU goes ahead with new sanctions over the ongoing crisis and conflict
13/22 17 September 2014
Despite the cease-fire and a law passed by the Ukrainian parliament on Tuesday granting greater autonomy to rebel-held parts of the east, civilian casualties continued to rise, adding to the estimated 3,000 people killed
14/22 16 November 2014
The fragile ceasefire gives way to an increased wave of military activity as artillery fire continues to rock the eastern Ukraine's pro-Russian rebel bastion of Donetsk
15/22 26 December 2014
A new round of ceasefire talks, scheduled on neutral ground in the Belariusian capital Minsk, are called off
16/22 12 January 2015
Soldiers in Debaltseve were forced to prepare heavy defences around the city; despite a brief respite to the fighting in eastern Ukraine, hostilities in Donetsk resumed at a level not seen since September 2014
17/22 21 January 2015
13 people are killed during shelling of bus in the rebel-held city of Donetsk
18/22 24 January 2015
Ten people were killed after pro-Russian separatists bombarded the east Ukrainian port city of Mariupol
19/22 2 February 2015
There was a dangerous shift in tempo as rebels bolstered troop numbers against government forces
20/22 11 February 2015
European leaders meet in Minsk and agree on a ceasefire in eastern Ukraine beginning on February 14. From left to right: Belarus President Alexander Lukashenko, Russian President Vladimir Putin, German Chancellor Angela Merkel, France's President Francois Hollande and Ukrainian President Petro Poroshenko.
MAXIM MALINOVSKY | AFP | Getty Images
21/22 13 February 2015
Pro-Russian rebels in the city of Gorlivka, in the Donetsk region, fire missiles at Ukrainian forces in Debaltseve. Fighting continued in Debaltseve for a number of days after the Minsk ceasefire began.
ANDREY BORODULIN | AFP | Getty Images
22/22 18 February 2015
Ukrainian soldiers repair the bullet-shattered windshield of their truck as their withdraw from the strategic town of Debaltseve. Following intense shelling from pro-Russian rebels, Ukrainian forces began to leave the town in the early hours of February 18.
Brendan Hoffman | Getty Images
In 1975, when Mr Putin was a university graduate about to start work as a KGB spy, the Soviets were in a position of strength, with a new generation of military hardware, wrote Professor Tom Nichols, of the US Naval War College, on The Federalist website last week. "The Soviets were at the top of their game," he said, and Mr Putin was someone "saturated with Soviet nostalgia". In that context, the spending on defence and build-up of troops has worried the West.
At the Nato summit it was agreed to add a 4,000-troop rapid-response force to an existing 13,000-strong force. Poland had requested that 10,000 Nato troops be stationed with heavy artillery in the country to counter Russian aggression. Polish Prime Minister Donald Tusk said he had hoped for more, but that: "This signal is very strong and our Eastern neighbour [Russia] cannot ignore it."
Referring to the alliance's commitment to the element of the Washington Treaty, whereby an attack on one nation constitutes an attack on all 28, Barack Obama visited Estonia before flying to Wales in a bid to reassure Eastern states that should Russia invade, Nato would respond.
"I say to the people of Estonia and the people of the Baltics, today we are bound by our treaty alliance," said Mr Obama. But only four Nato members (the US, Britain, Estonia, Greece) fulfil their obligation to spend at least 2 per cent of GDP on defence.
Nato Secretary General Anders Fogh Rasmussen said members had agreed to reverse the trend of falling defence budgets and "aim to move towards the existing Nato guideline".
According to IHS Jane's, Russia's defence budget was £35bn in 2011 and that had risen to £48bn this year – almost 5 per cent of GDP. The Kremlin is expected to approve spending of £60bn by 2016 – greater than Germany and France combined. This year was the first time Russia devoted a larger share of its GDP to military spending than the US since 2003.
"It is looking like, as a result of Russia's actions in Ukraine, that military spending is likely to start increasing in those countries that are nearest to Russia, the front line and the Nordic countries," Samuel Perlo-Freeman, head of the military expenditure project at the Stockholm International Peace Research Institute told The New York Times.
However, in a direct response to Russian involvement in Ukraine, on Wednesday, France's President François Hollande put on hold the delivery of a Mistral helicopter carrier – the Vladivostok – to Russia. The carrier, set to be delivered in weeks, was one of two in an agreement between the nations. The sale was due to be the biggest by a Nato member to Moscow, with Mr Hollande suggesting later that he would reassess the deal near the end of October.
Without an obvious military solution to the Ukraine crisis, the EU and US has launched a wave of economic sanctions against Russia.
On Friday night, even as the ceasefire agreed between Ukrainian President Petro Poroshenko and Mr Putin was observed, the EU issued further sanctions. These include making it harder for Russian state-owned firms to raise finance in Europe, and adding 24 people to a list of those barred from entry to the bloc, and whose assets in the EU are frozen.
"The implementation is expected on Monday," one senior EU diplomat told Reuters. "A ceasefire must hold for sanctions to be lifted."
Yesterday, Russia reacted to the threat. "If they [the new sanctions] are implemented of course there will be a reaction from our side," the Foreign Ministry said in a statement.Reuse content