Syria's war since 2011 has involved a host of regional and international players, created millions of refugees and displaced, and left more than 380,000 people dead.

At the heart of Syria's latest humanitarian crisis, locals call Idlib "the forgotten city", still paying the price for one day in the 1970s when the former president was pelted with tomatoes.

As it enters its tenth year, the war in Syria is anything but abating, as foreign powers scrap over a ravaged country where human suffering keeps reaching new levels.

On a Syrian highway, Hussein Abdel Hamid recently found himself trapped inside his car. A US army patrol had encountered Russian tanks down the road, neither allowing the other passage.

An airstrike on a rebel-held village in northwestern Syria hit a poultry farm where several displaced families were taking shelter early Thursday, killing at least 15 people including children and wounding several others, opposition activists said.

The activists blamed Russian warplanes for the strike on Maaret Musreen village, which is home to thousands of internally displaced people.

UN investigators warned Monday that Ankara might bear "criminal responsibility" for war crimes perpetrated against Kurds in northern Syria late last year, including the execution of a popular female politician.

The report comes as tensions soar between Turkey and Russian-backed Syrian forces following escalating clashes in the last rebel stronghold of Idlib, but is not directly linked to the latest unrest.  

Turkey-backed Syrian opposition fighters on Thursday retook a strategic northwestern town in Syria that was recently captured by government forces, and cut the highway linking the capital, Damascus, with the northern city of Aleppo days after the government reopened it for the first time since 2012.

The retaking of Saraqeb which sits on the highway is a setback for Syrian President Bashar Assad's forces who have scored major gains in a weeks long Russian-backed campaign in the last rebel stronghold in Idlib province. Officials had hailed the reopening of the motorway, known as the M5, as a major victory in the nine-year conflict.

Six pro-Syrian regime fighters were killed in overnight Israeli air strikes near Damascus, a war monitor said Monday. 

The UN refugee agency on Thursday appealed to Turkey to take in more refugees from Syria, as hundreds of thousands flee the regime's brutal assault on the last rebel enclave.

The UN High Commissioner for Human Rights on Tuesday called for the creation of humanitarian corridors in northwestern Syria, expressing horror at a Russian-backed regime offensive in the area.