* Washington, Moscow trade accusations over Geneva deadlock
* Kerry says Assad bent on military solution
* Lavrov says rebels' backers betting on military scenario
The United States accused Damascus on Monday of paralysing Geneva peace talks, while Russia said nations backing Syrian rebels were leaning toward a military, not a negotiated, outcome to a civil war whose death toll exceeds 140,000.
A second round of talks in Geneva broke up on Saturday with chief mediator Lakhdar Brahimi lamenting a failure to advance much beyond agreement on an agenda for a third round later.
U.S. Secretary of State John Kerry said President Bashar al-Assad's government was behind the impasse, aided and abetted by Russia and other allies of Damascus.
"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," he said in Jakarta during a trip to Asia and the Middle East.
Kerry appeared to be trying to tighten diplomatic pressure on Assad to reach a political settlement that would end government attacks on rebel-held areas and relieve the plight of tens of thousands of Syrians cut off from humanitarian aid.
Pressing Moscow to wring a more flexible stance from Assad, he said: "Russia needs to be a part of the solution", rather than helping the Syrian leader with arms and other support.
In Moscow, Russian Foreign Minister Sergei Lavrov hit back, citing "evidence that certain sponsors of the opposition are starting to create a new structure" bringing in Assad foes who have left the main opposition National Coalition.
"In other words, a course is being set to move away from the negotiations track and once again place bets on a military scenario," Interfax quoted Lavrov as saying at a joint news conference after talks with his Eritrean counterpart.
"MAGNET FOR TERRORISTS"
U.S. President Barack Obama said on Friday he was considering new ways to pressure Assad, but gave no details.
Russia has shielded Assad from Western and Arab pressure since the conflict began in March 2011, using its veto power to block U.N. Security Council resolutions and insisting that his exit from power cannot be a precondition for peace talks.
Moscow seemed to help Syrian government negotiators resist discussion of a transitional governing body for Syria at the Geneva talks last week by endorsing their demands that tackling "terrorism" should top the agenda. Russia has accused the sponsors of the rebels of pushing for "regime change".
The conflict has drawn thousands of foreign fighters into Syria to fight either for the mostly Sunni Muslim rebels or for Assad, whose Alawite sect is an offshoot of Shi'ite Islam.
Fighting has killed more than 140,000 people - more than 7,000 of them children - according to the Britain-based, pro-opposition Syrian Observatory for Human Rights, and is destabilising the country's neighbours.
Kerry derided the Syrian government's insistence that terrorism should be the main focus of the Geneva peace talks.
"Assad himself is a magnet for terrorists," he said, accusing him of pursuing "state-sanctioned terror against his own people" by indiscriminate bombing, starvation and torture.
The Geneva talks were initiated by Lavrov and Kerry, who jointly announced in May that they would seek to bring Assad's government and its opponents together to seek a solution.
The Syrian opposition negotiators have little sway over rebels fighting on the ground, with hardline Islamist factions that share al Qaeda's ideology eclipsing more moderate groups.
More evidence of disarray in the Western- and Arab-backed Syrian Free Army (FSA) emerged at the weekend when it sacked its leader and replaced him with a more experienced field commander.
The FSA's Supreme Military Council said it had replaced General Selim Idriss with Colonel Abdelilah al-Bashir because of "the ineffectiveness of the command in the past few months".