YOLA, Nigeria -- Seven children in Nigeria have been reunited with parents lost in the chaos of recent attacks by Islamic insurgents, but about 140 others have no idea if their families are alive or dead, officials said.

"There is this fear that some of those unaccompanied children might have lost their parents during the insurgents' attack on their villages" in northeast Nigeria, said Sa'ad Bello, the co-ordinator of five refugee camps hosting scores of lonely children in Yola, capital of Adamawa state.

He said he was optimistic that more reunions will come as residents return to towns that the military has retaken from extremists in recent weeks. Officials have reunited seven children with the help of the International Committee of the Red Cross, but 138 aged from 10 years and up remain alone, Bello said this week.

Suleiman Dauda, 12, said he ran into the bushes with neighbours when extremists attacked his village, Askira Uba, near Yola last year.

"I saw them kill my father, they slaughtered him like a ram. And up until now I don't know where my mother is," he told The Associated Press at Daware refugee camp in Yola.

More than 10,000 people have been killed in the past year and more than 1 million people are displaced within Nigeria because of the 5-year insurgency by the extremist Boko Haram group, according to the Washington-based Council for Foreign Relations. Hundreds of thousands of others have sought refuge across borders.

Haruna Hamman Furo, executive secretary of the Adamawa emergency agency, said the parents of some children may be among thousands of Nigerians who fled into neighbouring Cameroon. Officials are encouraging them to return home.

Faul reported from Johannesburg.