Eleven soldiers have been killed and five wounded in an attack on a military base in Mali as rival armed groups surrounded the city of Timbuktu.

There was no immediate claim of responsibility for the attack near the border with Burkina Faso on Sunday but armed groups, including al-Qaeda affiliates, have been increasingly active in recent months, attacking army posts beyond their usual strongholds in the north.

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"The post was attacked between 4am and 5am in Boulikessi," defence spokesman Abdoulaye Sidibe told the Reuters News Agency, adding that reinforcements had been sent to the area.

Armed group such as Ansar Dine have increased the frequency of their attacks over the past year.

In 2016, the group carried out scores of attacks, including on  United Nations peacekeepers, while spreading into the south and other areas previously deemed secure.

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Al-Qaeda's North African ally, al-Mourabitoun, claimed responsibility for an attack on a military camp in January that killed up to 60 people and wounded at least 100.

Mali is awash with weapons and home to several rival armed groups. Its northeast has been in a state of emergency, which gives security forces extra powers, since a wave of violence last year.

The north of the country fell under the control of Tuareg-led rebels and groups linked to al-Qaeda in 2012, who were largely ousted by a French-led assault in January 2013.

The implementation of a peace deal agreed in 2015, though, has been piecemeal and, despite the presence of at least 11,000 UN peacekeepers, armed groups who refused to sign are active across large parts of the country.

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Source: News agencies