Russia and the United States agreed Tuesday to invite Syria's warring parties to an international conference, possibly within this month, in an attempt to negotiate an end to their civil war.

Russian Foreign Minister Sergey Lavrov and U.S. Secretary of State John Kerry announced the agreement in Moscow, despite their nations' differences over the conflict, saying they would work to ensure both the Damascus government and the rebels fighting it would attend.

The aim, Reuters notes, is to revive an agreement to create a transitional government that was reached in Geneva last June but was never put into force, because it left open the question of what would happen to Syrian President Bashar al-Assad.

"We agreed that Russia and the United States will encourage both the Syria government and opposition groups to find a political solution," Lavrov told reporters at a concluding news conference that ended after midnight.

"The alternative [to a negotiated solution] is that there is even more violence. The alternative is that Syria heads closer to an abyss, if not over the abyss and into chaos," Kerry said.

"The alternative is that the humanitarian crisis will grow. The alternative is that there may be even a break up of Syria," said Kerry, who earlier held talks with Russian President Vladimir Putin in the Kremlin.

Russia has been a staunch ally of Assad, blocking new sanctions against Syria at the U.N. and supplying the government with arms. But referring to Assad, Lavrov said Moscow was not concerned by the fate of particular individuals.

"The task now is to convince the government and all the opposition groups ... to sit at the negotiating table," he said.

"At the conference that we are proposing to convene, Russia and the United States consider it necessary to work with the aim of convincing representatives of both the government and the opposition to together determine how they can fully implement the Geneva Communique," Lavrov added.

Kerry seemed to soften the U.S. postion on Assad’s possible role in the transition, ABC reports, saying that, while he individually could not see a way where Assad could continue to govern, the ultimate decision would not be up to him or the United States.

“Our position has been that it’s impossible for me, as an individual, to understand how Syria could possibly be governed in the future by a man who has committed the things that we know have taken place, but I’m not going to decide that tonight and am not going to decide that in the end,” Kerry said. “The Geneva communique says that the transitional government has to be chosen by mutual consent by the parties. Who are the parties? The parties are the current regime and the opposition.”