A young female suicide bomber on Tuesday killed at least six people and injured up to 28 others outside the main bus station in the northeastern Nigerian town of Damaturu.

A young female suicide bomber on Tuesday killed at least six people and injured up to 28 others outside the main bus station in the northeastern Nigerian town of Damaturu, witnesses and an official said.

No group or individual has claimed responsibility but Boko Haram terrorist group has in the past months used young women to carry out bloody suicide attacks in the northeast of the country.

"A young girl came around at 7:00 am (0600 GMT) and wanted to enter the bus station. She was denied entry because she refused to be searched by the security guards at the entrance," a witness, Sani Dankamasho, told AFP.

Boko Haram has stepped up attacks in three states in its northeastern heartland since President Muhammadu Buhari came to power on May 29, vowing to crush the group.

The terrorists have also carried out deadly ambushes across Nigeria's borders and in recent weeks suicide bombers, many of them women, have staged several attacks in Nigeria, Cameroon and Chad.