Boko Haram Maiduguri
A police officer stands at the scene of a bombing after at least 20 people were killed when a female suicide bomber detonated her explosives at a bus station in MaiduguriGetty

At least 13 people have been killed after two female suicide bombers blew themselves up at a crowded market and a military checkpoint in north-eastern Nigeria.

The attacks were carried out in the Malari village outside Maiduguri, capital of Borno state, the epicentre of terror group Boko Haram's insurgency.

Responsibility for the two blasts is likely to fall on the terrorists, who killed more than 100 people in several attacks at mosques in Kukawa on 2 July, a day after they attacked Monguno village, killing 40 people.

Who are Nigeria's Boko Haram terrorists?

Boko Haram (recently renamed Iswap) fights against Western influence in Nigeria and aims to impose its version of Sharia law on the country. The group declared an Islamic caliphate in Gwoza, along the Cameroon border, in August 2014.

Boko Haram has raided several cities in the north of the country in a bid to take control of more land.

Three states − Adamawa, Borno and Yobe − have been under a state of emergency since May 2013, due to Boko Haram's attacks.

The group has killed at least 2,600 people since the beginning of 2015. More than 200 have been killed since the beginning of June.

Witnesses told AP a teenage girl blew herself up at a market, which led to the deaths of 10 people. Minutes later, a woman in a taxi detonated her explosive and killed a soldier and two passengers.

Boko Haram is renowned for kidnapping women and children and forcing them to participate in attacks.

Earlier in June, a report by the BBC current affairs programme Panorama warned some 219 girls kidnapped by the insurgents from Chibok, Borno state, in April 2014, have been brainwashed to the point that they now torture Boko Haram's hostages and kill on behalf of the group.

The Nigerian government is being aided by mercenaries and troops from neighbouring countries Chad, Benin, Niger and Cameroon in its offensive against Boko Haram and has scored some successes since the military co-operation started in February.

The US announced it would send military trainers to help the Nigerian army improve its intelligence gathering and logistics.

During a visit to Chad in June, President Muhammadu Buhari renewed his commitment to fight the group, which has killed thousands of people since its insurgence started in 2009.

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