U.S. Secretary of State John Kerry blamed the Assad government for stalling Syrian peace talks and pressed Russia to stop supplying it weapons, telling Moscow it needed to be part of the solution, Reuters reported.
International mediator Lakhdar Brahimi said in Geneva on Saturday that the first two rounds of peace talks had not made much progress but that the two sides had agreed on an agenda for a third round at an unspecified date.
"The regime stonewalled. They did nothing except continue to drop barrel bombs on their own people and continue to destroy their own country. And I regret to say they are doing so with increased support from Iran, from Hezbollah and from Russia," Kerry told reporters in Jakarta on Monday during a trip to Asia and the Middle East.
Kerry appears to be trying to tighten diplomatic pressure on President Bashar al-Assad and reach a political settlement that can end government attacks on rebel-held areas and find a solution for tens of thousands of Syrians cut off from humanitarian assistance.
He was speaking before flying on Monday to the United Arab Emirates, which has supported the rebels.
Using unusually strong language, Kerry said: "Russia needs to be a part of the solution and not be contributing so many more weapons and so much more aid that they are in effect enabling Assad to double-down, which is creating an enormous problem."
Assad is still trying to win Syria's civil war militarily rather than find a solution through peace talks, he said.
"It is very clear that Bashar al-Assad is continuing to try to win this [on] the battlefield rather than to [go] to the negotiating table [with] good faith."
U.S. President Barack Obama said on Friday he was considering new ways to pressure the Assad government, but gave no details.
Russia has said the peace talks must not focus only on a transitional governing body, and has accused backers of the Syrian opposition of pushing for "regime change".
The three-year-old Syrian conflict has killed more than 130,000 people and is destabilizing the country's neighbors. The mainly Sunni Muslim rebels have drawn support from radical Sunni groups such as al Qaeda and other foreign militants.
Shi'ite countries and militias have thrown their weight behind Assad, who is from Syria's minority Alawite sect, an offshoot of Shi'ite Islam.
"As for Assad, who says he wants to talk about terrorism, Assad himself is a magnet for terrorists. He's the principal magnet of the region for attracting foreign fighters to Syria," Kerry said.
"Moreover, Assad himself is engaging in state-sanctioned terror against his own people. When you indiscriminately drop bombs on women and children, when starve people and torture people by the thousands, those are acts of terror."