GENEVA, March 2 -- U.S. Secretary of State John Kerry met with Russian Foreign Minister Sergei Lavrov here on Monday ahead of a new round of talks over Iran's nuclear program.

The two also disscussed the latest situation in Ukraine and Syria, a sourse close to Kerry said.

According to the source, some Iranian nuclear negotiators have arrived in Montreux, Switzerland, where the new round of Iran nuclear talks will start Monday evening between Kerry and his Iranian counterpart, Mohammad Javad Zarif.

The talks will be continued on Wednesday by senior diplomats from Iran and the P5+1 group, namely the U.S., Britain, France, Russia, China and Germany.

Last week, a senior U.S. official said the Iran nuclear talks have "made substantial progress," but "did not expect an agreement to be reached next week."

The last round of Iran unclear talks was held on Feb. 21-23 in Geneva.

It has been over a year since Iran and the world's major countries agreed to come back to the negotiating table for the Iranian nuclear program in 2013.

Under an interim deal between Iran and the P5+1 inked in November, 2013, Iran said it would suspend critical nuclear activities in return for limited ease of sanctions, with all sides seeking a comprehensive deal.

After missing twice self-imposed deadlines, the negotiators agreed in November 2014 to extend the deadline for another seven months and aimed to reach a political framework deal by the end of March.