Rebels have captured large parts of a Syrian police academy near Aleppo, after a fierce battle resulting in heavy loss of life, activists say.
Video emerged on Saturday apparently showing rebels breaking into the sprawling Khan al-Assal compound.
Almost 200 fighters had been killed on both sides over eight days, UK-based activist group the Syrian Observatory for Human Rights (SOHR) said.
The group's reports could not be independently confirmed.
Their account said more than 34 government soldiers and police died on Sunday alone - an apparent setback for government forces a day after the army announced it had regained control of villages on a major route linking the central city of Hama to Aleppo, with security "restored" to the northern city's airport.
A police source in Aleppo later confirmed that much of the academy had fallen into rebel hands, the AFP news agency reports.
In other developments:
- rebels fired several rockets at security forces headquarters in the capital Damascus, according to Al-Jazeera. It was not immediately clear if there were any casualties
- opposition leader Moaz al-Khatib visited rebel-held areas in northern Syria to strengthen ties between the main opposition coalition and rebel fighters on the ground
- President Bashar al-Assad, in an interview with the UK's Sunday Times newspaper, said it was "nonsense to suggest" that the conflict was about his future as leader.
The rebels took control of much of the police academy site at dawn on Sunday, the activist group said. They had been targeting the Khan al-Assal complex outside Aleppo for some time.
Almost 200 fighters and soldiers had been killed in the eight-day battle for the site, including 120 troops and police, Rami Abdel Rahman of SOHR told the AFP.
Footage had earlier shown dozens of fighters sheltering beside an outer wall as explosions could be seen apparently inside the academy's grounds.
The SOHR is one of the most prominent organisations documenting and reporting incidents and casualties in the Syrian conflict. The group says its reports are impartial, though its information cannot be verified.
It also reported on Sunday that rebels had seized a prison in northern Raqqa province.
In his Sunday Times interview, President Assad said the UK government was "naive, confused, unrealistic" in its approach to the conflict, accusing Prime Minister David Cameron's government of being determined to militarise the situation.
Although the UK says it supports the Syrian opposition without providing arms to the rebels, Foreign Secretary William Hague said on Sunday that "I don't rule anything out in the future".
Dismissing the Syrian leader's interview as "delusional", Mr Hague told the BBC that the UK "cannot just sit on the sidelines and watch this".
"I will not be announcing this week arms to the Syrian opposition," he insisted, indicating that a "wider range" of non-lethal equipment was now allowed under a European Union agreement.
But the longer the conflict continued, the greater the danger of extremism taking hold, he added.
President Assad said the Syrian government was ready to talk to anyone, including militants who laid down their weapons.
"We are not going to deal with terrorists who are determined to carry weapons," he said.
Since the Syrian uprising began in March 2011, an estimated 70,000 people have been killed.
Fighting has been reported throughout Syria and hundreds of thousands of refugees have fled to neighbouring countries.