Ceasefire in tatters as Assad troops attack Homs

Reports of heavy shelling and firing as first United Nations observers due to arrive to monitor truce

Shells pummelled the war-ravaged city of Homs yesterday in a flagrant breach of the country's shaky ceasefire just hours before an advance team of UN observers arrived to monitor the truce.

Each side accused the other of violating the UN-Arab League envoy Kofi Annan's ceasefire before the advance team of six United Nations "blue helmets" touched down in Damascus last night. The surge in violence threatens to derail international efforts to bring an end to the bloodshed with the deployment of any meaningful number of monitors dependent upon the ceasefire staying in place.

At least six neighbourhoods in Homs, an opposition hotbed, were said to have come under attack from President Bashar al-Assad's forces in the early hours of the morning after helicopters and spotter aircraft sought out their targets.

Video footage, purporting to be from the Khalidiya district, showed five missiles slam into nearby buildings and streets in less than a minute. One struck a tower a few hundred metres away from the cameraman, erupting in a huge fireball and sending bilious black smoke into the air. "The shelling has been extremely heavy," Abu Rami, an opposition activist in the Old City of Homs, said. "We counted more than 50 explosions between 6am and 8.30am and it still hasn't stopped.

"The shabiha [government militias] have also taken over the Gardenia tower, a very high building in al-Ghouta, and they are shooting towards al-Qarabees and al-Qusoor neighbourhoods with dushka machine-guns."

An initial team of 30 UN monitors are being sent to Syria after the UN Security Council, including Russia and China, passed a resolution on Saturday which authorised their deployment. The first six, who arrived last night, will begin work today, with the remaining two dozen joining them in the coming days.

The security situation is critical as a larger team of monitors - expected to number about 250 - will be dispatched only if the ceasefire is deemed to be holding.

British Foreign Secretary William Hague said the initial team urgently needed to be "beefed up".

"This number of people cannot possibly effectively monitor what is happening in the whole country," he told Sky News yesterday. "The plan will be for a much larger [team], more in the hundreds, of monitors to follow them provided the [ceasefire] plan is being implemented by all concerned."

Concerns were raised over the freedom the monitors will be given after a government spokeswoman, Bouthaina Shaaban, said yesterday that the government could be responsible for their safety only if it is involved with "all steps on the ground".

She confirmed that the number of monitors could rise to 250, but that Syria reserved the right to agree on the nationality of those participating. Syria is understood to be pushing for Russian and Eastern European monitors over those from Arab and Western states. Opposition activists on the ground yesterday scorned the size of the mission. "If you want to control the students at a primary school you need about 30 teachers but they think that 30 monitors can have an effect on the whole of Syria?" Waleed Fares, an activist from Khalidiya in Homs, said.

At least 10 people had been killed across the country as of yesterday afternoon, according to the Local Co-ordination Committees (LCC) - eight of them died in Homs.

Activists claimed that there was no aggression from the Free Syrian Army to spark the bombardment of the city, which followed reports of shelling on Saturday, but such details are impossible to verify with journalists denied access to the country. Citing a military source, the state news agency, Sana, said armed gangs had "hysterically escalated" their aggression since the ceasefire came into effect on Thursday.

"[Security forces], based on their duty to protect civilians and the country, will stop terrorist groups from continuing their criminal acts and the killing of civilians," it warned. The Syrian Observatory for Human Rights said clashes took place in the city of Aleppo in the early hours of yesterday morning after rebels attacked a police station.

Violence also raged in the Damascus suburbs, with the LCC reporting that heavy machine-guns had been fired by army troops "continuously for three hours" in Douma.