Executing a global squeeze play, the United States and its European allies on Thursday demanded an end to four decades of brutal family dictatorship in Syria and underscored the tough talk with new sanctions on President Bashar Assad's government.
The unified stance isolates Assad further as he presses a military campaign against major demonstrations. But the diplomacy left many questions unanswered, including how the demand for Assad's ouster can be backed up in the absence of any appetite for military intervention, and who inside the Syrian government or among the country's fragmented opposition might take his place.
The messages from Washington, London, Paris, Berlin and Brussels coincided with a U.N. report recommending that Syria be referred to the International Criminal Court for investigation of possible crimes against humanity, including summary executions, torturing prisoners and targeting children in the crackdown on demonstrations.
Much of Syria was quiet Thursday, although activists reported intense shooting around noon in the flash point city of Latakia.
Rights groups say Assad's forces have killed nearly 2,000 people since mid-March. The military assault on civilians has escalated since Ramadan began, with security forces killing hundreds and detaining thousands.
Activists said security forces killed 18 people across the country on Wednesday, the same day Assad assured U.N. Secretary-General Ban Ki-moon that military and police operations had stopped.
In Thursday's coordinated statements, President Obama and the leaders of Britain, France, Germany, Canada and the European Union called for Assad to resign, saying his repression of demonstrations inspired by this spring's Arab uprisings made him unfit to lead.
The resignation calls were the first explicit demands from the U.S. and its allies for Assad to step down, although condemnation of his actions had been growing for weeks.
Obama signed an executive order that gives his administration authority to impose sweeping new sanctions on Syria intended to further isolate Assad.
The order immediately bans the import into the United States of any Syrian petroleum or petroleum products. Syria is not a huge source of oil for the United States, but if European allies join the effort, it could significantly affect one of the government's top sources of revenue.
At the United Nations, Syria accused the United States of waging "a humanitarian and diplomatic war" against it by imposing sanctions and calling for Assad to resign.
Syria's U.N. Ambassador Bashar Ja'afari told reporters Thursday the only aim of the U.S. "war" is to instigate further violence in the country by sending "the wrong message to the terrorist armed groups that they are under American and Western protection."