Twin attacks on a Malian army base in the northern city of Timbuktu and in the centre of the country left dozens of soldiers dead, as well as at least a dozen assailants, security sources and local officials said on Monday.

Timbuktu came under attack and shells were also fired at the airport where heavy gunfire was heard, the army, local officials and residents said.

The army's general staff said in a statement it had "thwarted an attempt by terrorist fighters to infiltrate the Timbuktu camp" at around 10:00 am (local and GMT) with 14 attackers "neutralised", with no mention of other victims.

"The terrorists were quickly routed by the swift reaction of the men," the army said, adding that "31 suspected terrorists" had been arrested.

But the military was mourning the loss of at least 30 soldiers after reports emerged late on Monday of an attack on Sunday, likewise blamed on jihadists, at the Boulkessi army base in central Mali, near the border with Burkina Faso.

Security sources and a local official said they believed the death toll from that attack would likely rise.

"Our units on the ground report the death of 30 people on our side... Our men fought to the end but did not receive the necessary support," a security source in Bamako told AFP after the attack on what is one of the main military camps in the centre of the violence-plagued country.

The source added other soldiers remained missing.

"The toll is at least 60 soldiers killed," one local elected official told AFP on condition of anonymity.

A second security source told AFP there were "about 60 victims on the side of Malian forces", although that tally included "the dead, the missing and the soldiers taken hostage".

In a statement late Sunday, the army had indicated that troops had "responded vigorously" to the Boulkessi attack before withdrawing.

The statement went on to declare that "many men fought, some until their last breath" to defend their country and that ensuing military operations "have destroyed several terrorists grouped in places of retreat".

Junta-ruled Mali has since 2012 faced attacks from groups linked to Al-Qaeda and the Islamic State group as well as separatist movements and criminal gangs.

The army's general staff said Monday regarding the Timbuktu attack that it had thwarted an attempt by terrorist fighters to infiltrate the camp in the fabled desert city.

Later in the day, a security source said that operations in the camp were "already over" and that the attackers were "everywhere in the city".

"They did not raid the airport because the Russians are there. But they launched shells. It's hot everywhere," the source added.

A local official said the "terrorists" arrived in Timbuktu “with a vehicle packed with explosives".

"The vehicle exploded near the (military) camp," the official said.

UN staff were instructed in a message "to take shelter".

A local journalist speaking by telephone said "The city is under fire".

The ancient city of Timbuktu, once known as the "city of 333 saints" for the Muslim holy men buried there, was subject to major destruction while under the control of jihadists for several months in 2012.

The jihadists who swept into the city considered the shrines idolatrous and destroyed them with pickaxes and bulldozers.

The ancient city was peacefully retaken in late January 2013 with the support of French military forces under Operation Serval, deployed to halt the jihadists' advance in Mali.

Since seizing power in coups in 2020 and 2021, Mali's military rulers have broken the country's traditional ties with its former colonial power, France and moved closer to Russia.

Jihadist groups and the Malian army and its allies from the Russian paramilitary group Wagner are regularly accused of committing abuses against civilians.