Munich conference brings key players together amid questions over Syria, Ukraine, Iran

Top diplomats and defense officials are converging on Munich for a security conference renowned as a venue for backroom diplomacy and negotiations, with several international crises in the spotlight.

U.N.-Arab League mediator Lakhdar Brahimi was arriving hours after eight days of bitter negotiations between Syria's warring sides concluded in Geneva without tangible results. Russian Foreign Minister Sergey Lavrov, whose country has been a key supporter of the Syrian regime, and U.S. Secretary of State John Kerry as well as Defense Secretary Chuck Hagel also are expected in Munich.

Kerry plans to meet Ukrainian opposition leaders at the conference, which Ukraine's foreign minister also is to attend. Iran's Foreign Minister Mohammad Javad Zarif joins the meeting Sunday to address questions about his country's nuclear program.