Anti-regime activists took to the streets of rebel-held Mayadeen in eastern Syria on Wednesday for a third straight day to demand that jihadist al-Nusra Front fighters leave the town, a watchdog said.

"For the third day in a row, protests erupted in Mayadeen calling on the al-Nusra Front to leave the town," said the Syrian Observatory for Human Rights.

Syria's Muslim Brotherhood called on Wednesday for a week of action both in the strife-torn country and elsewhere to mark the two years since the revolt broke out against President Bashar Assad.

"We in the Muslim Brotherhood in Syria declare the week following March 15 a national week of solidarity with the Syrian people and their blessed revolution," the exiled opposition group said.

Interior Minister Marwan Charbel announced on Wednesday that the cabinet is committed to supporting families fleeing Syria “without any discrimination”, noting that it has become “urgent for Lebanon to receive aid to fulfill its humanitarian duty towards refugees”.

"Lebanon's resources have been exhausted and the country is unable to keep up with the increasing number of refugees,” Charbel said at the opening ceremony of the Arab Interior Ministers' security meeting in Saudi Arabia's Riyadh.

Syria's air force raided the strife-torn district of Baba Amr in the central city of Homs on Wednesday, four days after rebels infiltrated the neighborhood that has seen some of the two-year revolt's fiercest battles, a watchdog said.

The Syrian Observatory for Human Rights also said two children were killed and 30 people were wounded by mortar fire in Damascus.

A member of the European Union delegation in Syria was killed in a rocket attack on a suburb of Damascus, the EU's top diplomat said on Wednesday.

"I have learned today with great sadness of the tragic death on 12 March of Ahmad Shehadeh, a policy officer at the EU delegation in Syria," Catherine Ashton said in a statement.

The United Nations on Wednesday called for financial aid to assist one million Syrian refugees it says have been forced to flee a conflict that has become an "enormous threat" to the region.

"I appeal to all countries that want to help... I appeal to parliaments, governments to approve extraordinary funds to support the Syrian victims and the countries that receive them," said U.N. High Commissioner for Refugees Antonio Guterres.

The Dutch government has raised its terror threat level from "limited" to "substantial," saying Dutch citizens are traveling to Syria to fight in the civil war and could return battle-hardened, traumatized and further radicalized.

The country's National Coordinator for Security and Counterterrorism said in a statement Wednesday "the chance of an attack in the Netherlands or against Dutch interests abroad has risen."

Children are being increasingly recruited on the frontline in Syria's war, with both sides to the conflict using boys as soldiers and even human shields, a British charity said on Wednesday.

Save the Children said in a report marking two years of violence in Syria that two million children were innocent victims of the bloody conflict that the United Nations says has cost at least 70,000 lives.

Abu Ibrahim says he and his family are the only Christians left in Syria's devastated city of Deir Ezzor, and he is terrified Muslim extremists could make their already difficult life hell.

Yet every Sunday, he and the family peacefully hold prayers in a house they share with 15 soldiers from the rebel Free Syria Army (FSA), all Sunni Muslims.

Britain would consider ignoring a European Union arms ban and supplying weapons to Syrian rebels if it would help topple President Bashar Assad, Prime Minister David Cameron said Tuesday.

The EU last month amended its embargo to allow member nations to supply "non-lethal" equipment and training to the opposition but stopped short of lifting the embargo entirely.