Israel on Wednesday renewed its threat to attack Iranian military targets in Syria, after Tehran and Damascus signed an accord on security cooperation.

At least 27 people are being held by the Islamic State group in southern Syria, Human Rights Watch said Saturday as it deplored the hostage-taking as a "war crime".

Turkish Foreign Minister Mevlut Cavusoglu warned Friday that seeking a military solution in Syria's last rebel-held province of Idlib would lead to disaster.

The UN peace envoy for Syria will host Iran, Russia and Turkey for talks on drafting a new Syrian constitution on September 11-12, a United Nations spokeswoman said Friday. 

The leader of Syria's al-Qaida affiliate has vowed to fight on in Idlib province, the country's last major rebel stronghold, in the face of a possible government offensive.

Abu Mohammed al-Golani of the militant Levant Liberation Committee says state-sponsored surrenders of rebel groups, similar to those that recently occurred in southern Syria, won't happen in Idlib.

Saudi Arabia said early on Friday that it has contributed $100 million to northeast Syria for "stabilization projects" in areas once held by the Islamic State group and now controlled by U.S.-backed forces.

The Saudi Embassy in Washington said the money "will save lives, help facilitate the return of displaced Syrians and help ensure that ISIS cannot reemerge to threaten Syria, its neighbors, or plan attacks against the international community." ISIS is an alternate acronym for the militant group.

Lebanon has rejected the position of the head of the U.N. refugee agency, who said it was too early to talk about a mass return of Syrian refugees because the war-torn country is still too dangerous.

The Foreign Ministry said Tuesday that conditions in Syria now are stable in many cities and provinces.

Rebels controlling several towns in southern Syria were on Friday considering a deal for a regime takeover in exchange for an end to fierce bombing, state media and a monitor said.

Facing Russian and regime bombardment and abandoned by international backers Jordan and the United States, rebels in southern Syria are left with few options -- all of them unsavory. 

The rebels in southern Syria targeted by a major government offensive were long supported by Washington and seen as symbolizing relatively moderate opposition to Damascus.