UNITED NATIONS - UN Secretary-General Ban Ki-moon on Wednesday strongly condemned what he called an "appalling attack" on a university in Syria's northern city of Aleppo, which reportedly left more than 80 people killed and at least 160 others injured, saying that "Deliberating targeting of civilians and civilian targets constitutes a war crime."      

"The secretary-general strongly condemns the appalling attack at Aleppo University yesterday, in which scores of people have been reportedly killed and wounded," the deputy UN spokesman, Eduardo del Buey, said at a daily news briefing here.

Twin explosions rocked the faculty of Information Engineering in the University of Aleppo, on Tuesday. They were caused by two missiles fired by some gunmen not far away from the campus.

Aleppo, Syria's largest city, has emerged as the main focal point of deadly violence in the Middle East country's 22-month-old crisis.

"Deliberating targeting of civilians and civilian targets constitutes a war crime," del Buey said.  "Such heinous attacks are unacceptable and must stop immediately."        

"All combating parties in Syria must abide by their obligations under international humanitarian law," the spokesman said.

"The secretary-general sends his condolences to the families of those killed in this tragic attack," he said.  "He believes this latest atrocity should be promptly and fully investigated."

The secretary-general "also calls for a reflection by all Syrians about the degradation of a conflict that is tearing their nation apart, and stresses the urgent need for a peaceful political solution that ends the violence and meets the democratic aspirations of the Syrian people," he said.

The armed rebels in Aleppo have been pushing for territorial gains to control the city in the hope of establishing their de facto capital in the crucial slice of Syria.

Also on Wednesday, the Syrian Foreign Ministry urged the United Nations to condemn the attack on the university.

The Foreign Ministry, in letters sent to the United Nations, said that armed groups were responsible for the attack, which also led to the collapse of the student dormitory in the university, used by the Syrian government as a shelter for the displaced people.

Tuesday's attack was not the first, the ministry said, noting that armed militiamen have destroyed more than 2,362 schools during the long-standing crisis, which broke out in March 2011.

Syria's opposition has denied responsibility for the tragedy, saying that it was a result of airstrike by the government.