Dramatic footage of rocket attacks and tank assaults in the town of Homs in Syria have emerged as activists reported the heaviest bombardment of civilian areas since the start of anti-government protests.
Videos posted to YouTube by the British-born Syrian activist Danny Adbul Daymen appear to show a blasted landscape of civilian and residential buildings under apparently constant fire from rockets.
In one clip dated 8 February, which shows fire and smoke pouring from buildings, Daymen says:
"This is Homs, Baba Amr, you can see over there another rocket landed on one of the civilian's houses, this has been going on all day, since 5am.
"Why isn't the world helping us, where's the humanity in the world? Where is the f***king UN?" he asks. "This is happening every day … Where's America? … Are we animals dying here?"
In another video, also dated 8 February, Daymen stands over the lifeless body of what appear to be a small girl.
He says that the girl was killed by a mortar, and asks "is this what the UN is waiting for?"
In an interview with Sky News on Wednesday Daymen said children were being used as "human shields" and killed by government forces.
Daymen was previously interviewed by the BBC's Newsnight programme in September after returning from Syria following a previous stay in the besieged town of Homs.
"You get used to seeing bodies every day," he told the BBC in September. "You're going to have to even drag them off the floor, pick them up or even take them to hospital."
The veracity of Daymen's footage was impossible to verify independently, but corresponds to the reports of other activists emerging from the country.
Activists have reported that 50 people were killed in attacks overnight, as tanks rolled into residential areas.
Separate footage broadcast on Sky News showed a convoy of tanks rolling towards the city of Homs.
Another activist told Al Jazeera on Wednesday that there had been little retaliation by an armed opposition because the government forces were sending rocket attacks from miles away.
"Some areas are completely sieged. There is no internet, no landlines or mobile lines," Hadi Al-Abdallah told Al Jazeera.
Other witnesses told the Guardian newspaper that 13 Russian-made T-72 tanks and many heavy machine guns were being brought into Homs, and taking up positions in residential areas.
Foreign Policy published a photo essay of "Syria's Ground Zero" on Wednesday that showed the devastation in Homs after the crackdown by Assad's government forces.
The foreign minister of Russia Sergei Lavrov yesterday visited Damascus to meet President Bashar al-Assad, and was met by cheering crowds waving Russian flags.
Foreign Secretary William Hague spoke to Lavrov on Wedensday for around half an hour, and insisted that while Western countries were not contemplating military intervention in Syria President Bashar al Assad should step down.
The majority of British people oppose sending troops to Syria but do support the implementation of a no-fly zone, according to a poll by YouGov released on Wednesday.
Hague also tackled Lavrov about reported Russian arms sales to the regime. Lavrov retorted that such sales were not illegal.
In the Commons, David Cameron was dismissive of the Russia's unilateral attempt at a diplomatic intervention, saying he had "very little confidence" that it would end the fighting.
He told MPs at Prime Minister's Questions that the international community had now to work with Syrian opposition groups both inside and outside the country to co-ordinate a concerted opposition to President Assad's regime.
"I think the bloodshed in Syria is absolutely appalling. I think the Russians have to look at their consciences and realise what they have done," he said.
"But the rest of the world will keep on fighting as hard as it can to give the Syrian people a chance to choose their own future."
Russian prime minister Vladimir Putin warned on Wednesday that the world could not act like an "elephant in a china shop" over Syria and said that he could "not allow" anything similar to take place in his own country, where he has come under pressure from protesters who accuse his government of voter fraud.
According to AFP, Putin said: "We of course condemn all violence regardless of its source, but one cannot act like an elephant in a china shop.
"Help them, advise them, limit, for instance, their ability to use weapons but not interfere under any circumstances … A cult of violence has been coming to the fore in international affairs in the past decade. This cannot fail to cause concern."
China's foreign ministry spokesman said that its actions were "righteous and fair and any efforts to stoke discord in China-Arab relations will be in vain".
Responding to the violence the UN's top human rights official called for urgent international action to protect civilians, saying she was "appalled" by the assault.
"I am appalled by the Syrian government's willful assault on the city of Homs, and its use of artillery and other heavy weaponry in what appear to be indiscriminate attacks on civilian areas in the city," Navi Pillay, the UN's high commissioner for human rights, said in a statement.
"The failure of the Security Council to agree on firm collective action appears to have fuelled the Syrian government's readiness to massacre its own people in an effort to crush dissent".
Close to 6,000 people have died in Syria since anti-government protests began in the country in March 2011, the UN estimates.