Nigerian troops on Friday thwarted an attempt by four suspected Boko Haram suicide bombers to attack the restive northeastern city of Maiduguri, hotbed of the Islamist group, an army spokesman said.

At about 4.00 am (0300 GMT) troops "received a tip off about an impending attack in Maiduguri city by four suspected Boko Haram terrorists suicide bombers," army spokesman from Sambisa forest through cashew plantation," Colonel Sani Usman said in a statement.

"The ever vigilant troops responded decisively by intercepting and neutralising the suspected terrorists," he added.

Three soldiers sustained injuries during the incident, while two unexploded explosives devices were safely detonated.

Usman said troops also arrested three suspected Boko Haram insurgents at Nwagafete village, near Maiduguri.

Boko Haram has increasingly used suicide bombers in its almost seven-year rebellion, seeking to carve out an Islamic state in northeast Nigeria.

An estimated 20,000 people have been killed and more than 2.6 million people have fled their homes since the start of the violence.