U.S. Secretary of State John Kerry arrives in Russia Tuesday for talks on the war in Syria and other issues.
He is expected to meet with Russian President Vladimir Putin in Moscow.
Later, Kerry will hold a full bilateral meeting with Russian Foreign Minister Sergei Lavrov. They are expected to discuss a wide range of issues including Syria, the Iranian and North Korean nuclear programs, Afghanistan and trade.
Kerry and Lavrov have met several times in the past few months, but this will be Kerry's first trip to Moscow since taking the post of secretary of state in February. The two-day visit comes ahead of next month's meeting between U.S. President Barack Obama and Mr. Putin on the sidelines of the G-8 summit.
The United States and Russia have been at odds about how best to deal with the rebellion in Syria. Russia and China have repeatedly used their U.N. Security Council veto to block tougher United Nations action against Syrian President Bashar al-Assad.
Russia has supplied weapons to the Assad army. The United States and other countries support his opponents, although Washington says it is not providing weapons.
A senior State Department official said Monday that, although both the United States and Russia have expressed their support for a framework for a transition in Syria, it is uncertain whether an agreement will be reached during the Moscow meeting. The official says that "it is worth testing and trying to find some ways forward."