Nigeria's president Goodluck Jonathan has promised teenage Pakistani activist Malala Yousafzai that more than 200 schoolgirls kidnapped by Islamist militants will be returned home soon.

Malala, who became a global celebrity after surviving being shot in the head by the Taliban for campaigning for girls' education, was visiting Nigeria to support an international campaign for the release of the teenage students abducted in mid-April by the Islamist insurgent group Boko Haram.

The Pakistani teenager, who turned 17 on Saturday, at the weekend met parents of the schoolgirls snatched from the north-eastern village of Chibok by Boko Haram fighters.

The Nigerian girls' plight triggered an international #BringBackOurGirls Twitter campaign supported by Michelle Obama and Angelina Jolie.

This drew global attention to the war in Nigeria's north-east and the growing security risk that Boko Haram poses to Nigeria, Africa's leading energy producer.

But, with the girls still missing three months after their April 14 kidnap, Mr Jonathan faces criticism at home and abroad over the deteriorating security situation.

"The president promised me ... that the abducted girls will return to their homes soon," Malala, who has called the 219 missing students her "sisters", told a news conference after a 45-minute meeting with Mr Jonathan at the presidential villa.

She did not say whether the Nigerian leader had given her any fresh details of the military search operation for the girls to support his assurance.

Nigeria is receiving intelligence and surveillance assistance from the United States, Britain, France and other foreign allies but has so far shown little progress in getting the Chibok girls back.

Malala says she will continue campaign until girls are rescued

Malala says she will hold the Nigerian leader to his pledge to return the schoolgirls home.

"I will from now be counting days and will be looking. I can't stop this campaign until I see these girls return back to their families and continue their education," she said.

She added that Jonathan had also promised that once the missing girls were rescued, they would be given scholarships to go to school in any part of Nigeria.

Pressed by journalists on what the president had told her, Malala said Mr Jonathan described the girls' situation as "complicated" and that their lives could be put at risk by a military rescue attempt.

"But the president said these girls are his daughters and he is pained by their sufferings and that he has his own daughters and he can feel what they are feeling ... He has several options but ... he will choose the best to ensure the girls are released safely," she said.

Pakistani Taliban militants shot Malala for her passionate advocacy of women's right to education.

She survived after being airlifted to Britain for treatment, and has since become a symbol of defiance against the militants operating in the tribal areas along the Pakistan-Afghanistan border.

She has won the European Union's prestigious human rights award and was nominated for the Nobel Peace Prize last year.

Boko Haram, inspired by the Taliban, say they are fighting to establish an Islamic state in religiously mixed Nigeria.

The group, whose name means "Western education is sinful", has killed thousands and abducted hundreds since launching an uprising in 2009.

Now considered the main security threat to Nigeria, the insurgency is growing bolder.

Police said on Saturday they had uncovered a plot to bomb the Abuja transport network using suicide bombers and devices concealed in luggage at major bus stations.

Reuters