Rebels have been trying to break through a thin strip of government-controlled territory to reconnect insurgent areas in western Syria.

Syrian rebels broke through to besieged opposition-held areas in eastern Aleppo on Saturday in an assault on a major government military complex meant to end a month-long siege, insurgents and a monitoring group said.

Pro-government media outlets denied the siege had been broken and a US State Department official said the situation was “too fluid” to comment. The heavy fighting and air strikes reported from the area seemed to indicate any passage that may have been opened would be far from secure enough for civilians to travel through.

Rebels have been trying to break through a thin strip of government-controlled territory to reconnect insurgent areas in western Syria with their encircled sector of eastern Aleppo, in effect breaking a government siege begun last month.

The offensive against the government’s Ramousah military complex, which contains a number of military colleges, began on Friday.

Taking control of Ramousah and linking up with eastern Aleppo would isolate government-held western Aleppo by cutting the southern route out toward the capital Damascus.

Two rebel groups and a monitor said on Saturday they had broken the siege, but pro-government media outlets denied the claim and said the Syrian army was in fact regaining recently taken territory from rebels.

“We’ve seen reports but the situation is fluid and we aren’t going to provide battlefield updates,” the State Department official told Reuters.

Jabhat Fatah al-Sham, formerly the al Qaeda-affiliated Nusra Front, said in an online statement: “Fighters from outside the city met their brother fighters from inside the city, and work is under way to establish control over remaining positions to break the siege.”

A commander from more moderate rebel group also told Reuters the siege had been broken but said it was early days and matters were “not easy”.

The United Kingdom-based Syrian Observatory for Human Rights, which monitors the war, said intense fighting and heavy air strikes meant no secure corridor had yet been established between the two rebel-held territories.

Worst month for hospital attacks

In another report, the Observatory said an air strike near a hospital in northwestern Syria on Saturday killed 10 people including children and damaged the hospital. July was the worst month yet for attacks on medical facilities in the war-torn country, a medical charity said, with 43 recorded attacks on healthcare facilities in Syria.

The hospital is in Meles, about 15 km (9 miles) from Idlib city in rebel-held Idlib province. Syrian government and allied Russian warplanes operate in Syria but it was not known which aircraft carried out the strike.

The Observatory, in its report on the Aleppo fighting, said rebels had taken control of the Weaponry College, the main Artillery College, the Air Force Technical College and the Ramousah Garage area. Government forces still control the cement factory and some military housing.

“This is the biggest military and symbolic loss sustained by the regime, the Russians, the Iranians and Lebanon’s Hezbollah since the start of 2013,” the Observatory said, adding that heavy air strikes, thought to be from Russian planes, hit Aleppo on Saturday.

The Syrian military news agency said later on Saturday the Syrian army had restored control over the Artillery College and had made the rebels withdraw from the Weaponry College.

A witness said people in the streets of a part of eastern Aleppo briefly celebrated reports of the siege being broken before the sight of warplanes in the sky scattered them.

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