* Chibok abductee found in northeast Nigeria

* Witness says Amina Ali was carrying baby

* Girl to meet President Buhari on Thursday (Adds details, updates bullet point)

By Lanre Ola

MAIDUGURI, Nigeria, May 18 (Reuters) - A Nigerian teenager kidnapped by Boko Haram more than two years ago has been rescued, the first of more than 200 girls seized in a raid on their school in Chibok town to return from captivity in the insurgents' forest lair, officials said on Wednesday.

Soldiers working together with a civilian vigilante group rescued the girl and her four-month-old baby near Damboa in the remote northeast, army spokesman Sani Usman said. They also detained a "suspected Boko Haram terrorist" called Mohammed Hayatu who claimed to be the girl's husband, he added.

"Preliminary investigation shows that she is indeed one of the Chibok schoolgirls abducted by Boko Haram terrorists on 14th April 2014 in Chibok," Usman said in a statement.

Rights activists named the girl as Amina Ali Darsha Nkeki. They quoted her as saying her schoolmates remained in the Sambisa forest in the northeast, Boko Haram's biggest stronghold.

The girl will meet President Muhammadu Buhari in the capital, Abuja, on Thursday, his spokesman said, adding that she would be accompanied by the governor of Borno, the northeastern state in which Chibok is located.

A Reuters witness who saw the girl at the governor's office, in Maiduguri, said she seemed tired and was limping. Her age has not been disclosed but she appeared to be in her late teens.

Her rescue may give a boost to Buhari, a former military ruler who made crushing the Islamist militant Boko Haram insurgency a key pillar of his election campaign in 2015.

The military released a photograph of the girl, who was seated, clad in a Muslim headscarf and cradling a baby wrapped in a cloth while holding a plate of food.

Boko Haram seized 276 girls from their school in Chibok, northeast Nigeria, in April 2014, part of a seven-year-old insurgency to set up an Islamic state in the north that has killed some 15,000 people and displaced more than 2 million.

Dozens of the girls escaped in the initial melee in 2014 but more than 200 remained unaccounted for. Parents accused former president Goodluck Jonathan, Nigeria's leader at the time of the mass kidnapping, of not doing enough to track down the girls and bring them home.

"She (Amina) says all of the others are still in the Sambisa forest area, that they are heavily guarded," activists at #Bringbackourgirls said in a statement confirming her release.

Hoses Tsambido, chairman of the Chibok Community in the capital Abuja, told Reuters the girl was found on Tuesday in the Kulakasha area on the fringes of Sambisa Forest.

Usman said Ali and her alleged husband had been brought to Maiduguri "for further medical attention and screening".

Boko Haram, who last year pledged loyalty to Islamic State, have kidnapped hundreds of men, women and children in their campaign to carve out a mediaeval Islamist caliphate.

Under Buhari's command and aided by Nigeria's neighbours, the army has recaptured most territory once lost to Boko Haram but the group still regularly stages suicide bombings. (Reporting by Adaobi Tricia Nwaubani of Thomson Reuters Foundation, Lanre Ola and Ulf Laessing; Writing by Ed Cropley, Ulf Laessing and Alexis Akwagyiram, Editing by Mark Heinrich)

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