Secretary of State John Kerry commended the efforts of the Syrian opposition and lambasted Bashar Assad’s government’s uncooperative stance on Sunday, in a statement addressing the collapse of the UN-brokered peace talks in Geneva.

Saturday’s talks, which lasted less than half an hour, left the future of the negotiating process in doubt and no date was set for a third session.

While the opposition “demonstrated a courageous and mature seriousness of purpose and willingness to discuss all aspects of the conflict,” the regime “obstructed and filibustered,” Kerry said.

“The opposition delegation has regularly demonstrated that they are willing to engage constructively in the interests of all the Syrian people,” he continued. “In sharp contrast, we have seen a refusal to engage on the part of the regime.”

Kerry also sharply castigated the increased attacks against civilians launched by Assad while the talks were in session, a move the secretary deemed “reprehensible.”

“While it stalled in Geneva, the regime intensified its barbaric assault on its civilian population with barrel bombs and starvation. It has even gone as far as to add some of the opposition delegates at Geneva to a terrorist list and seize their assets,” Kerry said.

Kerry appealed to all parties to take advantage of the recess to work on a solution to the civil war.

“There’s no recess in the suffering of the Syrian people,” he said.

Kerry’s comments come as Syria’s Foreign Minister Walid al-Moallem accused the United States of trying to create a “negative climate” for dialogue at the second round of peace talks in Geneva, while its chief negotiator attributed the lack of solutions to Israel and the US.

Syrian Deputy Prime Minister Walid al-Mouallem speaks during the 68th session of the General Assembly at United Nations headquarters, on Monday, September 30, 2013. (photo credit: AP/Seth Wenig)

Syrian Deputy Prime Minister Walid al-Mouallem speaks during the 68th session of the General Assembly at United Nations headquarters, on Monday, September 30, 2013. (photo credit: AP/Seth Wenig)

“Everybody is trying his best to undermine the whole process, either Israel or unfortunately the Americans, or even the sponsors of the so-called coalition and the opposition,” Syria’s top negotiator Bashar Jaafari told reporters after a second round of talks wrapped up fruitlessly.

Jaafari, who is also Syria’s ambassador to the United Nations headquarters in New York, pointed to President Barack Obama’s pledge Friday to take unspecified “intermediate steps” to pressure the regime.

He also accused Washington of pushing the Syrian rebels to “escalate militarily” notably by stepping up fighting on the country’s southern border with Jordan.

“Those people are not really committed towards guaranteeing the success of the Geneva conference. On the contrary, there was no goodwill at all,” Jaafari said.

Despite the blame-trading and deadlock, Jaafari insisted the process was not over.

“We will be back,” he said.

“We don’t have an impasse. We are still in negotiation. We didn’t say that we failed.”

Washington is backing the opposition in Syria’s conflict. Over 130,000 Syrians have been killed since the civil war erupted in March 2011.