Iran will help push militants out of the last Syrian rebel stronghold with "the least human cost", Foreign Minister Mohammad Javad Zarif said on Tuesday. 

The U.S. envoy for Syria was in Ankara on Tuesday to discuss the latest developments in the war-torn country with Turkish officials as an offensive against rebel-held Idlib appeared imminent.

Six protesters were killed on Tuesday in the oil-rich southern Iraqi city of Basra, an official said, which has been shaken by two months of demonstrations.

Nearly four million Iraqis displaced by the war on the Islamic State group have returned to their homes, the U.N. migration agency said in a report released Tuesday.

Spanish Foreign Minister Josep Borrell and his Palestinian counterpart warned Tuesday that Washington was losing its traditional mediating role in the Israeli-Palestinian conflict by "aligning" with Israel.

The United States warned Damascus Tuesday it will respond "swiftly and appropriately" if it uses chemical weapons against its people.

The warning came amid signs that Syrian President Bashar al-Assad was preparing an offensive in Idlib province that the United Nations has said poses the threat of a humanitarian disaster.

An Israeli military official said Tuesday the army had carried out some 200 strikes in Syria over the past 18 months against mainly Iranian targets, a rare confirmation of such action.

The U.N. urged Russia and Turkey Tuesday to help avert a "bloodbath" in Idlib, as renewed Russian airstrikes on the Syria's last major rebel stronghold killed least nine civilians, according to a monitor.

The U.N. mission in Libya said on Tuesday a ceasefire agreement has been reached to end deadly clashes that have rocked the capital Tripoli for the past week.

Israeli missile strikes targeted Iranian military positions in the Syrian provinces of Hama and Tartus on Tuesday, the Syrian Observatory for Human Rights monitoring group said.