French police were on Wednesday probing whether a man seen in a video released by the Islamic State group purporting to show the execution of an Arab Israeli was close to French jihadist gunman Mohamed Merah.

In the video, a youth identifying himself as 19-year-old Mohammed Said Ismail Musallam is shown kneeling in front of a boy who appears to be no more than 12-years-old. A man stands at his side.

Syrian government forces are responsible for killing nearly 600 doctors and medical workers during the four-year war, Physicians for Human Rights said Wednesday, calling the attacks a crime against humanity.

The New York-based rights group accused President Bashar Assad's forces of "systematically" targeting hospitals, clinics and medical personnel since the conflict began in 2011.

A Japanese tourism agency said Wednesday its website was hijacked by hackers who displayed a message purportedly from the Islamic State (IS) group, less than two months after the group claimed to have beheaded two Japanese hostages.

The hack follows a series of similar attacks on websites including a community futsal team and a Tokyo camera shop, public broadcaster NHK reported.

The Islamic State jihadist group launched a major offensive Wednesday to try to capture a strategic town on the Syrian-Turkish border, leaving dozens dead in clashes, a monitor said.

"Fighters from the Islamic State group started a huge assault towards Ras al-Ain and were able to take over a village nearby," the Syrian Observatory for Human Rights said.

As Syria's civil war rages into a fifth year, the daily suffering of its people has been overshadowed by atrocities committed by the Islamic State group that have sparked international horror.

Four years after anti-regime protests broke out on March 15, 2011, jihadists control large tracts of territory, a defiant President Bashar Assad is clinging to power and revolutionary dreams have faded.

Forces fighting the Islamic State group have cut critical communication and supply lines used by the extremists between Syria and Iraq after a two-week operation, the U.S.-led coalition said Tuesday.

Backed by air strikes, the forces "overcame ISIL (IS) resistance" in northeastern Syria near the strategic town of Tal Hamis -- once an IS stronghold -- and "denied the terrorist group its freedom of maneuver in the area," the Combined Joint Task Force said in a statement. 

Three London schoolgirls who fled to Syria are believed to have stolen family jewellery to fund their travel, police said Tuesday as the trio's relatives expressed disbelief at their actions.

Schoolfriends Kadiza Sultana, 16, and 15-year-olds Shamima Begum and Amira Abase, left their homes last month and flew to Istanbul, from where they are believed to have joined Islamic State (IS) jihadists in Syria.

An Israeli army officer was wounded Tuesday by gunfire from the Syrian side of the Golan Heights, the military said, in what was believed to have been a deliberate attack.

"During a routine IDF (Israel defense force) activity in the Golan Heights, shots were fired at an IDF force," a statement read.

The head of the U.N. agency for Palestinian refugees accompanied the first aid convoy in three months to enter the besieged Yarmuk camp in the Syrian capital on Tuesday.

Pierre Krahenbuhl said it was "totally unacceptable" that some 18,000 residents of Yarmuk had not received aid for so long.

The Progressive Socialist Party clarified Tuesday afternoon the content of an interview for party chief MP Walid Jumblat with As Safir newspaper, noting that his son, Taymour, will run normally in parliamentary elections “just like other candidates.”

The line saying “Jumblat will hand over his Shouf parliamentary seat to his son Taymour in May” was “inaccurate”, the PSP said in a statement.