KIDAL: Gunmen attacked and fired rockets at a UN peacekeeping base in Kidal in northern Mali on Saturday, causing an unspecified number of casualties, a spokesman for the UN force in Mali (MINUSMA) said.

"The attack happened at around 4 a.m. (0400 GMT). Four or five rockets landed inside the base. Quite a few people were wounded but it's too early for a precise number," MINUSMA spokesman Olivier Salgado told Reuters.

French troops and the UN force are struggling to stabilise the former French colony where Islamist militants attacked a hotel in the capital on Nov. 20 and killed 20 people.

Three Islamist militant groups - al Qaeda in the Islamic Maghreb (AQMI), its splinter group al Mourabitoun and Massina Liberation Front (MLF) - claimed the attack on the Radisson Blu hotel. Security analysts say they could be collaborating.

Northern Mali was occupied by Islamist fighters, some with links to al Qaeda, for most of 2012. They were driven out by a French-led military operation, but violence has continued.

Other West African governments are also battling Islamist militants. Boko Haram, the leading such group in the region, has this year extended its attacks from Nigeria to neighbouring states of Niger, Cameroon and Chad.