US President Barack Obama and Russian President Vladimir Putin spoke by phone Tuesday to discuss Syria’s civil war and preparations for the peace conference starting this week in Switzerland aimed at ending the conflict, the White House said in a statement.

The two presidents reviewed the upcoming Geneva II talks as well as reviewing efforts to destroy Syria’s chemical weapons. US-Russian cooperation in the implementation of the Joint Plan of Action that aims to rollback key aspects of Iran’s nuclear program was also assessed.

According to the Russian Tass news agency, the Kremlin said in a statement that the phone conversation, that was initiated by the Americans, was “businesslike and constructive.”

The Geneva II conference is set to begin Wednesday in the Swiss resort city of Montreux, with high-ranking delegations from the United States, Russia and close to 40 other countries attending. Face-to-face negotiations between the Syrian government and its opponents — the first of the uprising — are to start Friday in Geneva.

However, the main bloc within the Syrian National Coalition — the Syrian National Council — issued late-night statement on Monday saying it was quitting the Coalition in protest over its decision to attend the talks, according to AFP.

The Council stated that taking part in the talks would renege on its commitments to not enter negotiations until Syrian President Bashar Assad leaves power. The ruinous Syrian civil war, that began in 2011, has killed over 100,000 people and generated millions of refugees.

In addition Obama and Putin discussed how to have a safe and secure Olympics in Sochi amid security concerns for next month’s winter games.

Russian officials were hunting down three potential suicide bombers, including one believed in be in Sochi. The State Department has told those attending the games to remain attentive to personal security. US lawmakers have also expressed serious concerns.

Separately, US Gen. Martin E. Dempsey, the chairman of the Joint Chiefs of Staff, held discussions with Russian counterpart Gen. Valery V. Gerasimov to discuss Olympic security.

The US is considering allowing Russia the use of sophisticated US-made devices — which detect and jam cell phone or radio signals used by terrorists — for the Olympic games, The New York Times reported.