Syrian government helicopters dropped barrel bombs on opposition-held districts of the northern city of Aleppo on Monday, killing at least 31 people including several children, an NGO said.

Some of the wounded were in a serious condition after the strikes on the Sukkari and Ashrafiyeh neighborhoods, the Syrian Observatory for Human Rights said.

Some 100 men from the Syrian city of Homs, who turned themselves in after escaping an army siege, have been sent to perform their military service, the governor said Monday.

Activists expressed concern over the fate of the men, with one warning that "there is a real chance they might get assassinated".

Recent military successes by the Islamic State of Iraq and the Levant (ISIL) will encourage a new wave of European jihadist fighters to join the conflict, the Dutch government said Monday.

"I'm concerned that ISIL has become an important group to join for jihadist fighters from the Netherlands and Europe," said Dick Schoof, who heads the Dutch government's anti-terror agency NCTV.

The United Nations appealed on Monday for $27 million (20 million euros) to help hundreds of thousands of Palestinian refugees trapped in Syria buy food during the Muslim holy month of Ramadan.

"As we come up to Ramadan, we can foresee a prospect of thousands of Palestinian refugees going hungry because very simply they do not have enough money to buy food," Pierre Krahenbuhl, commissioner general of the U.N. Relief and Works Agency for Palestine refugees (UNRWA), told reporters in Amman.

A week after Syria announced a wide-ranging amnesty, state media, a newspaper close to the government, and activists have offered wildly contradictory figures on the number of prisoners freed.

Activists said they could confirm the release of only several dozen prisoners and were skeptical of other numbers being bandied about.

Spanish police arrested eight people in pre-dawn raids in Madrid on Monday against a jihadist recruitment network led by a former Guantanamo Bay inmate, the government said.

The cell found and dispatched recruits for Islamic State of Iraq and the Levant (ISIL) militants based in Syria and Iraq, Spain's interior ministry said in a statement.

Gunmen coming from Syria on Sunday crossed a Lebanese Army checkpoint in the Bekaa border town of Arsal before fleeing the area as troops opened fire, state-run National News Agency reported.

"Three gunmen coming from Syrian territory in a GMC SUV crossed an army checkpoint in Arsal's Wadi Ata, which prompted troops to fire towards them,” NNA said.

Syria has freed after 21 years in jail an ex-horse rider known to have been an equestrian rival of one of President Bashar Assad's late brothers, reports said Sunday.

The release of Adnan Qassar is part of a wide-reaching amnesty that Assad decreed last week, and has seen some 1,500 people freed from the war-ravaged country's prisons, said the Syrian Observatory for Human Rights.

Germany's federal police on Sunday announced the arrest of a French national suspected of fighting for radical jihadists in Syria.

A spokesman told Agence France Presse that the man was picked up in Berlin late Saturday after flying in from Istanbul and was believed to have spent time in Syria where he allegedly joined the jihadist Islamic State of Iraq and the Levant.

Syria's army has been pounding for 24 hours major bases of the Islamic State of Iraq and the Levant in coordination with the Baghdad government, a monitor said Sunday.

The strikes against ISIL -- which has spearheaded a week-long jihadist offensive in Iraq – have been more intense than ever, said the Syrian Observatory for Human Rights.