A coalition of armed anti-government groups, the Army of Conquest, has captured all of a strategically important military base in the northern city of Aleppo, Syrian rebels said.

The opposition forces, who already control the countryside and areas southwest and east of Aleppo, said on Saturday that they now control the base in the Ramosa quarter in southwestern Aleppo.

The Syrian Observatory for Human Rights (SOHR), a UK-based monitoring group, also said on Saturday that the same armed rebel coalition "took control of the armament school, where there is a large amount of ammunition, and a large part of the artillery school".

READ MORE: Life among barrel bombs for Aleppo's children

However, Syrian state television disputed the claim, saying that government forces pushed the rebel fighters back, killing hundreds of them in the process.

Saturday's conflicting claims came a day after the Army of Conquest said they had stormed the major army artillery base, and were fighting to take the other military academies adjoining it.

The artillery base is almost 2km from the besieged opposition area.

It has a huge supply of ammunition and is used regularly to shell parts of the city held by opposition forces.

"There are two suicide bombers who have driven into regime posts inside the artillery base," Abu al-Walid, a fighter with Ahrar al-Sham, told Reuters news agency on Friday, adding that there was fighting inside the base.

Hundreds of fighters clashed with government troops only a few hundred metres from each other in parts of the artillery base after breaking into government defences around the heavily fortified compound, the rebels said.

For its part, the Syrian army said the attack on the artillery base and two major military academies had been foiled, with hundreds of fighters killed and much of their armoured vehicles and tanks destroyed.

It said the assault was the biggest by rebels against government-held areas in the past few years.

"Today there was a large-scale attack by the terrorist armed groups and they used all types of weapons, but we are fighting this attack and will defeat them," Brigadier-General Deeb Bazi, the head of one of the military academies targeted, told Reuters.

OPINION: Syria's civil war is a post-factual conflict