Iran on Wednesday denied a report that one of its nuclear scientists was killed in an ambush near the capital of its war-torn ally Syria.

"There are no Iranian nuclear scientists in Syria," said Deputy Foreign Minister Hassan Ghashghavi, quoted by state news agency IRNA.

Syrian authorities detained a veteran dissident living in Damascus on Wednesday as he tried to leave the country to visit his family in Spain, his party said.

Louay Hussein is part of the regime-tolerated opposition, but is especially outspoken and recently published a stinging statement that said President Bashar Assad's regime is "collapsing".

A car bomb near a main Baghdad square followed by a suicide bombing at a nearby police headquarters killed 11 people and wounded 23 Wednesday, security and medical officials said.

A police colonel said six of the dead and 11 of the wounded from the blasts in west Baghdad were policemen.

Turkey could scrap a controversial plan to buy missile defense systems from China that alarmed the United States and its Western allies, Turkish and European sources said Wednesday.

Key NATO member Turkey said in September last year it was entering negotiations with the China Precision Machinery Export-Import Corporation (CPMIEC) to acquire its first long-range anti-missile systems.

Justice Minister Ashraf Rifi vowed to object on a condition set by Syrian authorities which demanded the Lebanese state to “officially appeal Damascus for help” to engage in a prisoners swap with jihadists to guarantee the safe release of the abducted Lebanese soldiers and policemen.

Rifi stressed in comments to al-Liwaa newspaper on Wednesday that Syria's conditions are “completely rejected.”

Hizbullah is reportedly boosting and reactivating the Resistance Brigades by recruiting fighters from all sects in the north and the west of the Bekaa valley and offering them training and arms to combat the Islamic State group and other organizations.

According to An Nahar newspaper published on Wednesday, several youth are directly training with the Iranian Revolutionary Guards in return for a hefty salary ranging between $1,500 and $2,500.

U.S. military action against Islamic State jihadists in Iraq and Syria began on a small scale three months ago but has steadily expanded in size and scope, raising the stakes for Washington, experts say.

The mission has morphed from protecting religious minorities in Iraq to a vow to "destroy" the IS group in both Syria and Iraq, a dramatic shift for an American president who as a candidate was an outspoken opponent of the previous U.S. war in Iraq.

A Russian court in Chechnya's capital of Grozny has sentenced a man to two years for fighting in Syria against Bashar al-Assad's regime, a report said Tuesday.

The man, Said Mazhayev, fought in the rebel Free Syrian Army from November 2013 to January 2014 and was charged with participating in a foreign armed group when he returned home, according to case details on the prosecution's webpage.

The U.N. refugee agency said Tuesday it had been forced to slash the number of people it can help prepare for winter in conflict-ravaged Syria and Iraq for lack of funds.

"The whole humanitarian community is facing shortfalls. People are becoming numb," said Amin Awad, who heads UNHCR's Middle East and North Africa bureau, lamenting that his agency was having to make "tough choices".

Syria has freed around 11,000 detainees since President Bashar Assad declared a general amnesty in June, the country's National Reconciliation Minister Ali Haidar said.

However, rights groups including the Syrian Observatory for Human Rights say 200,000 people are still languishing in government jails.