ABUJA (Reuters) - Nigeria’s presidency said on Monday it plans to negotiate for the release of 110 girls abducted from a school in the northeastern town of Dapchi last month, rather than use a military operation to free them by force.

The kidnapping is one of the largest since the jihadist group Boko Haram abducted more than 270 schoolgirls from the northeastern town of Chibok in 2014. Some of the Chibok girls have been freed after what security sources say were ransom payments; around 100 are still being held.

Nigeria is grappling with an insurgency by Boko Haram that has killed at least 20,000 people since 2009. Members of the group are suspected of the latest kidnapping, on Feb. 19, in the state of Yobe.

President Muhammadu Buhari, a 75-year-old former military ruler, discussed the use of negotiations during a meeting with U.S. Secretary of State Rex Tillerson in the capital, Abuja, the presidency said.

“Nigeria prefers to have schoolgirls abducted by Boko Haram from Chibok and Dapchi back alive, and that is why it has chosen negotiation, rather than a military option,” Buhari’s office said in an emailed statement issued by the president’s spokesman.

“President Buhari added that Nigeria was working in concert with international organisations and negotiators, to ensure that the girls were released unharmed by their captors,” the presidency statement said.

The issue of security has become politically charged in Nigeria less than a year before a presidential election. Buhari is touring areas hit by security problems and this week will visit the state where the schoolgirls were abducted, the statement said.

Tillerson was in Nigeria for the last stop in a week-long tour of African countries, his first trip to the continent as Secretary of State, during which he has emphasised security partnerships. He visited Ethiopia, Kenya, Djibouti and Chad before arriving in Nigeria’s capital.

The emailed statement also said Buhari thanked the U.S. for assistance rendered in the fight against Boko Haram, noting that Nigerian forces are good but need assistance with training and equipment.