Twin car bombs killed at least 22 people in the Syrian city of Idlib on Wednesday as universities nationwide held a day of mourning for 87 people killed in explosions on the student campus in second city Aleppo.
The bombings had the hallmarks of operations staged by the jihadist Al-Nusra Front, a rebel group which has a strong presence on the ground in northwestern Syria and is blacklisted by the United States as a "terrorist" organisation.
"The first explosion took place in Al-Ziraa Square and the second explosion took place in Al-Mutlaq Square, killing 22 civilians and wounding 30," the state SANA news agency reported, blaming "terrorists" for the blasts.
Idlib city remains under the control of forces loyal to President Bashar al-Assad but most of the rest of the northwestern province on the border with Turkey is in the hands of rebels fighting to oust him.
The Syrian Observatory for Human Rights gave a higher toll of 24 dead and said most were soldiers. The Britain-based watchdog said there were three bombs in all and that many of the wounded were in critical condition.
"After taking the airbase at Taftanaz (on January 11), the city of Idlib has become the rebels' new target," Observatory directory Rami Abdel Rahman told AFP.
The Observatory said that the death toll from Tuesday's blasts at Aleppo University could top 100 as many of the wounded are in critical condition, which would make it one of the bloodiest attacks of the 22-month conflict.
No one has claimed responsibility for the explosions, and the government and the rebels have blamed each other.
Opposition activists said government jets carried out an air strike, but the army said rebels fired rockets at the campus, which lies in a government-controlled area of the battleground northern city.
"The General Command of the Army sees in the targeting of academics, colleges and universities further proof of the killers' dark methods, and of an ideology that belongs in the past," a statement from the military said.
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In a letter addressed to UN Secretary General Bank Ki-moon and the UN Security Council, the foreign ministry called on the international community to "denounce the terrorist massacre."
In an allusion to Western support for France's military intervention against Islamist rebels in Mali, the ministry said "some countries in the world are practising two-faced politics, by supporting terrorism in Syria and denouncing it in others."
Higher Education Minister Mohammed Yahia Moalla called a nationwide "day of mourning" on Wednesday, state television reported.
Near the capital, the army sent reinforcements to the town of Daraya as warplanes and rockets bombarded the rebel enclave, the Observatory said.
"The army's assault is insanely violent. The shelling is continuous, it has been so intense in the past hours. There are many injured people," said Daraya-based activist Abu Kinan.
In Tehran talks with Syrian Prime Minister Wael al-Halqi late on Tuesday, President Mahmoud Ahmadinejad vowed no change in Iran's staunch support for President Bashar al-Assad's regime, state media said.
"We hope that the plots and enmities against the Syrian nation will soon end and peace and security can be established in the country," the official IRNA news agency quoted Ahmadinejad as saying.
Ahmadinejad said the two countries' "cooperation in different fields is beneficial to Iran and Syria as well as regional nations."
More than 60,000 people have been killed in Syria since the uprising against Assad's rule erupted in March 2011, according to the United Nations.
The World Food Programme said on Wednesday that it would quickly try to distribute aid to an additional one million Syrians after Damascus gave the green light for it to work with local aid organisations to reach more of those in need.
Previously most of the UN agency's food aid was delivered through the Syrian Arab Red Crescent, which was overstretched and only able to provide help to some 1.5 million Syrians a month.