James Cleverly’s comments came after he gave a speech in Estonia in which he spoke about deterring Russian President Vladimir Putin’s aggression by “strengthening our collective security”, and made the case for Sweden to swiftly join Nato.
Answering questions from the media afterwards, Mr Cleverly was asked about Tuesday’s drone attack on Moscow and whether Ukraine had the right to attack Russian territory.
He said: “I don’t have details, and I am not going to speculate about the nature of the drone attacks in Moscow. So what I’m about to say are more general points, rather than on that specific incident.
“Ukraine does have the legitimate right to defend itself. It has the legitimate right to do so within its own borders, of course, but it does also have the right to project force beyond its borders to undermine Russia’s ability to project force into Ukraine itself.
“So legitimate military targets beyond its own border are part of Ukraine’s self-defence. And we should recognise that.
“That is not to say that I have any particular assessment over the attacks in Moscow, but more broadly military targets beyond its own border are internationally recognised as being legitimate as part of a nation’s self-defence.”
Russian air defences stopped eight drones converging on Moscow, officials said on Tuesday, in an attack Russian authorities blamed on Ukraine.
The attack came as Russia continued its bombardment of Kyiv with a third assault on the Ukrainian capital in 24 hours.
Ukraine made no immediate comment on the attack on Moscow, which would be one of its deepest and most daring strikes into Russia since the Kremlin launched its full-scale invasion of Ukraine more than 15 months ago.
Meanwhile, Downing Street said it was confident no British-supplied equipment was used in the drone attack.
The Prime Minister’s official spokesman said he would not “speculate on the origin of the attacks”, adding: “Obviously what we have seen are significant attacks on Kyiv in recent days, including on civilians.”
In his speech in Estonia, delivered alongside his Estonian counterpart Margus Tsahkna, Mr Cleverly said: “Today, Margus and I discussed the Nato summit taking place in Vilnius in July.
“We agreed that we must bolster support for Ukraine and ensure that Nato adapts to an increasingly contested and volatile security environment.
“And I know that we both feel it’s important that Sweden joins us at the table in Vilnius too, as a fully fledged member of Nato, and as an important ally to us all. Swedish accession will make us all safer and stronger.”
Mr Cleverly said the UK was “very proud” to lead Nato’s enhanced forward presence in Estonia, adding: “Let’s remind ourselves that in 1726 Britain sent her then Baltic fleet to the coast of Tallinn to deter the Russian fleet from attacking Denmark and Sweden.
“History doesn’t always repeat itself, but it does have a habit of rhyming. Admiral Sir Charles Wager and his fleet’s presence deterred Russia almost 300 years ago. And I hope that our presence here today will continue to do the same.
“As the great Lord Nelson observed, we cannot command the winds and the weather, but we can brace ourselves against the gales and ready ourselves for the storm to come. So whatever Russia decides to do next in Ukraine, or indeed anywhere else, we are prepared. And we will continue to cultivate the rich relationship between our two countries.”
The Foreign Secretary arrived in Tallinn on Tuesday for his first official visit to Estonia, where he met members of the government and visited the Royal Navy’s HMS Albion in the Baltic Sea.
He will head to Norway on Wednesday for a gathering of Nato foreign ministers in Oslo, where he is expected to push for Sweden to join the military alliance before the summit in July.
Objections from Turkey and Hungary have slowed the process for Swedish membership.