WASHINGTON, May 5 (Xinhua) -- U.S. Secretary of State Rex Tillerson on Friday discussed with his Russian counterpart Sergey Lavrov about efforts to reduce the conflict in Syria, the U.S. State Department said.

"The Secretary of State spoke by phone with Russian Foreign Minister Lavrov today about the efforts to de-escalate the ongoing conflict in Syria," according to a State Department statement.

"The secretary looks forward to further meetings with the foreign minister to discuss the respective roles of the United States and Russia in de-escalating the conflict and supporting the talks in Geneva to move the political solution forward," the statement added.

The exchange occurred one day after Russia, Iran and Turkey signed a memorandum in Kazakhstan's capital Astana on the creation of four safe zones in war-torn Syria.

In another statement on Thursday, the U.S. State Department voiced concerns about Iran's role as a guarantor of the new memorandum to reduce violence in certain areas of Syria.