The UN Security Council has authorised an African-led military force to try to oust Islamists from northern Mali.

The council unanimously approved giving the force an initial one-year mandate.

It said it should use "all necessary measures" to help Mali recover the north of the country from "terrorist, extremist and armed groups".

Armed groups, some linked to al-Qaeda, took control of northern Mali after a military coup in March and established a harsh form of Islamic law.