MOSCOW, May 16 (Xinhua) -- Russian President Vladimir Putin and his Turkish counterpart Recep Tayyip Erdogan Wednesday expressed serious concerns about the many deaths in recent violent clashes in the Gaza Strip.

In a phone conversation, the two leaders paid particular attention to the mass protests in the Palestinian territories in connection with the opening of the U.S. embassy in Jerusalem, the Kremlin said in a press release.

"The Russian side underlined the importance of refraining from violence and the need to establish an effective negotiating process in order to find mutually acceptable solutions based on relevant United Nations decisions," it said.

Putin and Erdogan also discussed the Syrian settlement and Russian-Turkish cooperation in the energy sector.

Mass protests of Palestinians took place in the Gaza Strip on Monday when the U.S embassy was transferred from Tel Aviv to Jerusalem, an ancient city holy to Jews, Muslims and Christians.

At least 60 Palestinians, including six children, were reportedly killed and more than 1,300 others injured by live ammunition and rubber bullets, said UN Special Coordinator for the Middle East Peace Process Nickolay Mladenov.