Syria has drawn strong condemnation for its deadly crackdown on protesters in the central city of Hama, with human rights campaigners hinting at the possibility of the country's leaders being tried for crimes against humanity.
Tuesday's attack in Hama killed 22 people and left more than 80 wounded as troops pushed through improvised road blocks made by residents, according to human rights groups.
As international condemnation piled on Syria, Amnesty International said a deadly siege in May in Talkalakh, which lasted less than a week, may have amounted to crimes against humanity as a result of deaths of protesters in custody, torture and arbitrary detention.
"The accounts we have heard from witnesses to events in [Talkalakh] paint a deeply disturbing picture of systematic, targeted abuses to crush dissent," said Philip Luther, Amnesty International's Middle East and North Africa deputy director.
"Most of the crimes described in this report would fall within the jurisdiction of the International Criminal Court. But the UN Security Council must first refer the situation in Syria to the court's prosecutor."
The London-based rights group's report, which was released on Wednesday, said the attacks "appear to be part of a widespread, as well as systematic, attack against the civilian population".
Al Jazeera's Rula Amin, reporting from Beirut, said on Wednesday that the protests in Hama pose a "very serious problem to the regime".
Government forces had pulled out of the city earlier in the protests, Amin explained, creating a political vacuum which encouraged people to take to the streets on Fridays, culminating in last week's mass rally against Syrian President Bashar al-Assad last week.
But Assad sacked the city's governor on Saturday and mass arrests followed.
Western powers condemned Syria for the crackdown, with William Hague, the British foreign secretary, saying Syria's actions raised questions on whether it was committed to any reforms.
"Violent repression in Hama will only further undermine the regime's legitimacy and raise serious questions about whether it is committed to the reforms it has recently announced," Hague said in a statement on Tuesday.
Victoria Nuland, spokesperson of the US state department, said: "We urge the government of Syria to immediately halt its intimidation and arrest campaign, to pull its security forces back from Hama and other cities, and to allow Syrians to express their opinions freely so that a genuine transition to democracy can take place."
"The government of Syria claims it is interested in dialogue at the same time that it is attacking and massing forces in Hama, where demonstrations have been nothing but peaceful," she added.
Some residents of Hama, the scene of a crackdown by Assad's father nearly 30 years ago, had sought to halt any military advance by blocking roads between neighbourhoods with garbage containers, and by burning tyres, wood and metal.
"Security forces had to use bulldozers in order to re-open the roads ... The government now says it was armed groups that were trying to block the roads," Amin said.
Rights groups say that more than 1,300 civilians have been killed and 10,000 people arrested by security forces since the revolt against Assad's rule began in mid-March.
France, which has taken a tougher stance on Syria than its Western allies, said on Tuesday there were signs Russia was beginning to question its Syrian stance.
Russia has opposed a French-led UN Security Council draft resolution, which condemns Assad's government and urges it to adopt rapid change, but stopped short of imposing sanctions or allowing military action.
Moscow has accused Western countries of exploiting the Security Council resolution that authorised limited military intervention in Libya and says it fears that could happen again in Syria.
Speaking of French negotiations with Russia, Alain Juppe, France's foreign minister said: "I think the point of no return has been crossed and the ability for Assad to make reforms today is zero in view of what has happened," Juppe said.
France has also failed to convince South Africa, India and Brazil to vote in favour, leaving the resolution short of the minimum 11 of 15 votes it feels it needs to submit the resolution.