Russia and the United States agreed on Tuesday to try to arrange an international conference this month on ending the civil war in Syria, and said both sides in the conflict should take part.

Russian Foreign Minister Sergei Lavrov and U.S. Secretary of State John Kerry announced the agreement after talks in Moscow that also involved President Vladimir Putin, despite their countries' differences over the conflict.

The aim is to revive efforts to secure a negotiated political solution that involves the creation of a transitional government in Syria after more than two years of violence that has killed more than 70,000 people.

"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 told a joint news conference with Lavrov.

"The alternative is that the humanitarian crisis will grow. The alternative is that there may be even a break up of Syria."

Washington and Moscow agreed on the need for a transitional government at a conference in Geneva last June but left open the question of what would happen to Syrian President Bashar Assad. But, referring to Assad, Lavrov said Russia was not concerned by the fate "certain" individuals.  

Common ground

At the start of talks in the Kremlin, Kerry told Putin that efforts to end the conflict are among issues on which the former Cold War foes can work together.

"The United States believes that we share some very significant common interests with respect to Syria - stability in the region, not having extremists creating problems throughout the region and elsewhere," Kerry said.

He said he hoped the two countries would be able to find "common ground" on Syria. They both endorsed a plan for a political solution for Syria last June but have differed over how to implement it.

Kerry said U.S. President Barack Obama also believes Russia and the United States could cooperate "significantly" on issues including North Korea, Iran and economic ties, which both sides say have not lived up to their potential.

Kerry's visit is part of an effort to improve relations between Russia and the United States, which have been strained by disagreements over issues including human rights and Syria since Putin's return to the Kremlin a year ago.