A Syrian school has been hit in a government airstrike in the opposition-held district of Aleppo, killing at least 19 people, including 10 children, activists have reported.

According to the UK-based Syrian Observatory for Human Rights, an anti-government monitoring group, Wednesday’s attack hit the Ein Jalout school in the eastern part of Aleppo.

Activist videos showed the bodies of the 10 children were laid on the ground of a local hospital wrapped in sheets and bulldozers removing rubble from the smashed building, the Associated Press news agency reported.

UNICEF said in a statement it was "outraged by the latest wave of attacks perpetrated against schools and other civilian targets across Syria."

Thousands of Syrian children have died in the three-year conflict, which began as an uprising against President Bashar al-Assad's rule and has now become a civil war that has killed more than 150,000 people and displaced millions.

Ongoing violence

Aleppo, Syria’s largest city, has borne the brunt of the violence.

Forces loyal to Assad have been carrying out airstrikes and dropping crude barrel bombs in rebel-held districts in the eastern part of the city, at times hitting schools, mosques and markets.

The airstrike follows a mortar attack and double car bombing on Wednesday that killed at least 54 civilians in pro-Assad districts of Homs and Damascus.

Assad announced earlier this week that he would run for re-election. In a televised campaign-style appearance on Tuesday, Assad and his wife Asma met with parents who lost their only sons in the conflict.

Humanitarian aid failure

Meanwhile, United Nations humanitarian chief Valerie Amos said that a Security Council measure designed to provide aid to millions of Syrians was not working.

The chances of alleviating the misery of more than nine million people, who urgently need help, have worsened since the body implemented Resolution 2139 in February, Amos said in a statement on Wednesday.

Less than ten percent of the 242,000 people living in besieged areas received assistance within the last four weeks.

"The humanitarian situation in Syria is beyond catastrophic. More than two months after a UN resolution to alleviate the suffering of civilians and end war crimes was adopted, the situation there has only worsened," said Jose Luis Diaz, from the UN office in New York.

The 15-member panel is in deadlock. Some would like to refer Syria to the International Criminal Court (ICC) or introduce targeted sanctions against those violating the resolution.

PHOTO CAPTION

This photo provided by the anti-government activist group Aleppo Media Center (AMC), which has been authenticated based on its contents and other AP reporting, shows a damaged school that was hit by a Syrian government air strike in Aleppo, Syria, Wednesday, April 30, 2014.

Aljazeera