Two Gulf Arab nations have joined Saudi Arabia in recalling their ambassadors from Syria in the wake of bloody crackdown, further isolating President Bashar Assad's regime.
Kuwait's deputy prime minister and foreign minister said his country was pulling its envoy home "for consultation".
Sheik Mohammed Sabah al-Salem Al Sabah said Gulf foreign ministers will meet soon to discuss the Syrian situation.
Bahraini Foreign Minister Khalid bin Ahmed Al Khalifa announced that the island kingdom was also recalling its ambassador.
Bahrain earlier this year got help from its Gulf neighbours in putting down its own uprisings. Activists say at least 32 died in those protests.
The latest moves came as a besieged Syrian city faced fresh artillery fire.
The renewed violence in the eastern city of Deir el-Zour came a day after at least 42 people were killed there in an intensifying government crackdown on protesters.
"We heard very loud explosions, and now there's intermittent gunfire," an activist in the city said. He said people were too terrified to take the wounded to government hospitals, instead treating them at home or in makeshift hospitals.
Deir el-Zour is in an oil-rich but largely impoverished region of Syria known for its well-armed clans and tribes whose ties extend across eastern Syrian and into Iraq.
Syrian troops also stormed Maaret al-Numan in the northern province of Idlib at dawn, activists said.
More than 300 people have died in the past week, the bloodiest in the five-month uprising against Assad's authoritarian rule.
The government's crackdown on mostly peaceful, unarmed protesters demanding political reforms and an end to the Assad family's 40-year rule has left more than 1,700 dead since March, according to activists and human rights groups.
Assad's regime disputes the toll and blames a foreign conspiracy for the unrest, which at times has brought hundreds of thousands of protesters into the streets.
Condemnation of the Syrian government spread to the internet, where the hacking group known as Anonymous claimed credit for vandalising the Syrian military's website.
The site quickly became unavailable, but screenshots circulated online showed the group's trademark headless suit and a message addressed to the Syrian people saying that "the world stands with you against the brutal regime".