The White House has accused the Syrian regime of causing "tremendous suffering" in its successful bid to reclaim the strategic town of Qusair. Separately US, Russian and UN efforts to organize peace talks have failed.
The United States denounced President Bashar al-Assad's government on Thursday over its 17-day assault on Qusair, near the Lebanese border. It said Syrian troops owed their success to Hezbollah fighters backed by Iran.
"The United States condemns in the strongest possible terms the Assad regime's assault on Qusair, which has killed untold numbers of civilians and is causing tremendous humanitarian suffering," White House spokesman Jay Carney said in a statement.
"It is clear that the regime could not contest the opposition's control of Qusair on its own, and is depending upon Hezbollah and Iran to do its work for it in Qusair," Carney said.
He went on to repeat a White House call for Iran and Hezbollah to withdraw all troops from Syria, adding that Hezbollah's involvement posed a direct threat to Lebanon's stability.
Opposition fighters confirmed they had been ousted from the town on Wednesday, roughly a year after first seizing it. The government had earlier claimed a "heroic victory" in the offensive launched on May 19. "Our heroic armed forces have returned security and stability [to the area]," the government said in a statement broadcast on Syrian state television.
As a crucial supply route for both government and rebel forces, the town had become the focal point of Syria's 27-month conflict. Witnesses said the town, formerly home to 40,000 people, had been left in ruins.
No date for peace talks
The regime's triumph in Qusair underlines the potentially game-changing role of Hezbollah in the Syrian civil war. Analysts suggest it could also embolden al-Assad to push for military victory rather than enter into peace talks.
The United States, Russia and the United Nations are seeking to bring rebel and regime representatives to the negotiating table in Geneva. Although UN-Arab League envoy Lakhdar Brahimi conceded Wednesday that no date had yet been set for face-to-face talks.
"It will not be possible to hold this conference in June," Brahimi told reporters in Geneva, adding that he hoped for a July date.
Al-Assad's regime has agreed "in principle" to attend the talks. The opposition, however, has demanded a prior commitment that the president will step down.
According to UN estimates more than 80,000 people have been killed in Syria since the conflict erupted in March 2011.
ccp/jm (AFP, Reuters, AP)