A bomb attack has claimed the lives of at least six people and injured more than 40 others in Nigeria’s northeastern state of Yobe.

A young female bomber detonated her bomb outside the main bus station in the town of Damaturu, the capital of Yobe, during the early hours of Tuesday.

Witnesses said they saw a "young girl" approaching the station and refusing to be frisked by security guards at the gate before blowing herself up.

"A private taxi... drove out of the park. As soon as the car came close, she detonated the explosives. Six people in the car were killed," AFP quoted Sani Dankamasho, a bystander, as saying. At least 42 people were also injured in the blast.

"The dead have been evacuated to a mortuary while the injured victims are currently being attended to by health and emergency workers," Yobe local government spokesman Abdulahhi Bego said in a statement.

No group or individual has claimed responsibility for the bombing, but Boko Haram Takfiri terrorists have in the past used young women to carry out similar attacks in the restive northeast of Nigeria.

Separately, witnesses and police reported a second attack about 10 minutes after the station blast, in which a bomber managed only to kill himself and slightly wound a bystander on the outskirts of the same town.

"There were two suicide blasts in Damaturu today. The first one happened outside the motor park and the second one occurred in Pompomari on the outskirts of Damaturu. But only the bomber has died in the second blast," said Toyin Gbadegesin, a spokesman for Yobe police.

The attacks came just hours after UN Secretary General Ban Ki-moon wrapped up a two-day visit to the violence-hit African country.

Ban was in Nigeria to commemorate the fourth anniversary of a deadly attack claimed by Boko Haram in the capital, Abuja.

On August 26, 2011, two dozen people lost their lives when a bomb-laden car exploded at the UN House in Abuja, the headquarters for about 400 employees.

Boko Haram has stepped up attacks in Yobe and other states in northeastern Nigeria since President Muhammadu Buhari came to power on May 29.

According to an AFP count, bombings, a wave of raids and attacks have left at least 1,000 people dead in Nigeria alone in less than three months.

The Boko Haram militancy began in 2009, when the terrorist group started an armed rebellion against the government of Nigeria. Amnesty International says 17,000 people have been killed since then.

The violence has spilled over into Nigeria’s neighboring countries. Soldiers from Nigeria, Chad, Cameroon and Niger have been battling the terrorists in recent months.