The Nigerian army says increased raids, ambushes and bombardments aimed at Boko Haram militants have resulted in more than 70 members of the Islamist terror group surrendering.

Cape Town  - Almost 70 members of the Islamist terrorist group Boko Haram have surrendered in north-eastern Nigeria.

The insurgents gave themselves up over the past three weeks after repeated air and artillery bombardments as well as ambushes conducted by soldiers, army spokesman Onyema Nwachukwu said in a statement on Thursday.

"The relentless offensive forced many of them to surrender to the troops," said Nwachukwu.

The captured insurgents were now "undergoing a rehabilitation and deradicalization," the spokesman added.  

Boko Haram poses a steady threat to communities in the north-east of Nigeria and has also launched offensives in neighbouring Chad, Niger and Cameroon.

The group's goal is to enforce a strict interpretation of Islamic law, or sharia.

Since 2009, tens of thousands of people have died at the hands of the Sunni fundamentalists in Nigeria, Chad, Cameroon and Niger.

According to the United Nations, an estimated 2.7 million people in the region have fled their homes due to Boko Haram.