Public executions, amputations, lashings and mock crucifixion are a regular fixture in jihadist-controled areas of Syria, a U.N. probe charged Wednesday, also accusing Damascus of repeatedly using chemical weapons against civilians.

"Executions in public spaces have become a common spectacle on Fridays" in parts of Syria under control of the jihadist Islamic State (IS), the independent Commission of Inquiry on the human rights situation in Syria said.

The Islamic State militant group is holding hostage a young American woman who was doing humanitarian aid work in Syria, a family representative said. The 26-year-old woman is the third American known to have been kidnapped by the militant group.

The Islamic State group recently threatened to kill American hostages to avenge the crushing airstrikes in Iraq against militants advancing on Mount Sinjar and the Kurdish capital of Irbil.

Social Affairs Minister Rashid Derbas estimated that 8,000 Iraqi refugees fleeing the expansion of the Islamic State in their country have arrived in Lebanon.

“So far 1,000 Iraqi refugees registered with the U.N. refugee agency” UNHCR, Derbas said in comments published in al-Joumhouria newspaper.

Head of Arsal Municipality Ali al-Hujeiri denied on Wednesday that Syrian gunmen infiltrated the town after the Lebanese army deployed in the area.

“The rumors are inaccurate,” Hujeiri told al-Liwaa newspaper, calling on those stating the false reports to “have mercy on Arsal and its residents who have been harmed.”

Lebanese Forces Leader Samir Geagea revealed on Wednesday that he will propose again his solution to the presidential deadlock, stressing that the stalemate should end swiftly.

Geagea said in remarks published in An Nahar newspaper that he will seek with his March 14 allies to suggest anew his solution to end the presidential stalemate.

An American fighting for the Islamic State was killed over the weekend in Syria, U.S. officials said Tuesday, underlining growing concerns about Westerners signing up for extremist groups in the Middle East.

U.S. spy agencies face a difficult task in tracking Islamic jihadists in Syria, as Washington lacks a robust network of informants and faces threats to its drone fleet, experts and former officials say.

An American journalist held for nearly two years by militants linked to al-Qaida in Syria returned to the United States late Tuesday, two days after Qatar negotiated his release, his family said.

Saudi police have arrested eight people in the northwest suspected of recruiting young people to join the Islamic State jihadist group in Iraq and Syria, the interior ministry said Tuesday.

Police in Tamir, 150 kilometers (100 miles) north of Riyadh, arrested eight people "who deluded young people into joining foreign extremist groups," the ministry said in a statement carried by the official SPA news agency.

The Australian government on Tuesday announced a Aus$64 million (US$60 million) package to help prevent youngsters from being radicalized and joining extremist groups in the Middle East.

The funding follows a warning from spy chief David Irvine this month that the bloody conflicts in Iraq and Syria are creating a new generation of militants.