France's prime minister revealed Monday that seven French nationals or residents, including six converts to Islam, had committed suicide attacks in Syria and Iraq.

Speaking in parliament as he defended controversial draft spy laws, Manuel Valls said that of the hundreds of French people who had made their way to Islamic State-held territory, seven had died staging the suicide operations.

Schools in rebel-held areas of Syria's Aleppo city will be closed for at least a week after bloody air raids on civilian areas, a monitor and activists said Monday.

On Sunday, an air strike on a school in the city's opposition-controlled east killed five children, three women teachers and a man.

A verdict in the case of three Syrian activists accused of "promoting terrorist acts", including leading dissident Mazen Darwish, has been set for April 15, their lawyer said on Monday.

"The head of the terrorism court set a verdict date for the cases of Mazen Darwish and his colleagues Hani Zaitani and Hussein Ghreir for April 15, after it was delayed a number of times," Michel Shammas told AFP.

Nine Lebanese truck drivers, who had been stranded at the Syrian-Jordanian border following clashes between rebels and Syrian government troops, returned to Beirut on Monday.

A plane carrying eight truckers landed at Rafik Hariri International Airport before noon.

An Australian airport website was offline Monday after being taken over by pro-Islamic State hackers who published messages supporting the jihadist group.

Police said hackers appeared to have targeted the web host used by the Hobart International Airport in Tasmania and not the facility itself, and no direct threats were made. 

The number of Europeans fighting with jihadist groups in Syria could exceed 6,000, a top EU official told a French newspaper Monday.

"At the European level, we estimate that 5,000-6,000 individuals have left for Syria," EU Justice Commissioner Vera Jouriva told Le Figaro in an interview, adding the true number was likely to be far higher due to the difficulty of tracking foreign fighters in the conflict.

Kurdish militia made headway on Sunday into Syria's northern Raqa province, where the extremist Islamic State group has set up its de facto capital, Kurdish officials and a monitor said.

The Kurdish People's Protection Units (YPG) "took over a large cement factory and three villages" northwest of the town of Ain Issa, said the Syrian Observatory for Human Rights.

Agriculture Minister Akram Shehayyeb announced Sunday that the eight Lebanese truck drivers who were still stranded in Syria have crossed into Jordan and are now in the custody of Jordanian authorities, as efforts continued to unveil the fate of a ninth trucker.

The drivers “are doing well and will arrive in Beirut tomorrow aboard a Middle East Airlines plane,” said Shehayyeb, who was tasked by cabinet to follow up on the case.

A Syrian regime air strike hit a school in the main northern city of Aleppo on Sunday killing five children and four other civilians, a monitoring group said.

"Military aircraft struck a school in east Aleppo city and killed five children, three female teachers and one man," said Rami Abdel Rahman, head of the Syrian Observatory for Human Rights. 

At least 35 civilians were killed on Saturday as government forces and rebel fighters exchanged fire in Syria's main northern city of Aleppo, a monitoring group said.

The Syrian Observatory for Human Rights said the dead included 18 civilians -- two of them children -- killed in regime air strikes on Al-Maadi and Sheikh al-Lutfi, two rebel-held neighborhoods in east Aleppo.