MOSCOW (AP) — Secretary of State John Kerry says he's hoping to find some "common ground" with Russia on how to deal with Syria's civil war.

He spoke as he entered a meeting with Russian President Vladimir Putin in Moscow. The U.S. is looking for Russia to take a tougher stand on Syria.

Kerry also thanked Putin for Russia's cooperation on the Boston Marathon bombing investigation.

Kerry says the U.S. and Russia share common interests in Syria -- including stability in the region, and preventing extremism from growing.

Through an interpreter, Putin said he looked forward to working together with U.S. leaders on current problems.

Kerry arrived in Moscow earlier today for the high-level talks with Russia -- which is the most powerful ally of Syrian President Bashar Assad's regime.