U.N. Secretary-General Ban Ki-moon is alarmed at escalating tensions along the Syrian-Turkish border and is warning that the risk of regional conflict and threat to international peace is increasing.

The U.N. chief is calling on all parties "to abandon the use of violence, exercise maximum restraint and exert all efforts to move toward a political solution," Ban's spokesman, Martin Nesirky, said Thursday.

Nesirky said Lakhdar Brahimi, the U.N.-Arab League envoy, has been in contact with Turkish and Syrian officials "to encourage an easing of tensions."

Meanwhile, the U.N. Security Council remains divided over Syria's cross-border shelling that killed five Turkish civilians, with Russia opposing a strong condemnation of its Syrian ally.

U.S. U.N. Ambassador Susan Rice said council experts were meeting to try to agree on a text.