African peacekeepers on Monday announced the seizure of a large weapons cache near Bangui airport in the capital of the strife-torn Central African Republic.

"This is an important arsenal that would be enough to keep a large part of Bangui under siege," said a source in the MISCA force who asked to remain anonymous.

He said Chadian soldiers found the weapons during an operation lasting several hours late last Thursday, acting on a tipoff from local residents.

The haul included more than 10,000 rounds of 12.7 mm bullets, two anti-air missiles, three rocket-propelled grenades, six mortars, around 50 assault rifles and a score of anti-personnel mines.

"We are unsure of the origin of the arsenal," the MISCA source said.

The Central African Republic was plunged into chaos by a March 2013 coup that ousted president Francois Bozize, sparking a cycle of revenge attacks between the Muslim minority and Christian majority.

The violence has left thousands dead and displaced around a quarter of the impoverished country's 4.6 million people, and the United Nations is investigating genocide allegations.

The former colonial power France, which deployed 1,600 men in early December in support of the 6,000-strong MISCA force, last week announced that it would send 400 more.

The European Union will deploy a 1,000-strong peacekeeping mission next month.