MINNA, Nigeria (Reuters) - Gunmen have released students abducted three months ago from an Islamic school in north-central Nigerian state of Niger, two parents told Reuters on Thursday.

       Around 136 school children were taken from the school in Tegina town in May but on Monday the school's owner said that six had died of illness.

       The releases were confirmed by an official who asked not to be named because the government planned to issue a statement once they have the children.

       One parent, Mallam Saidu Tegina, said by phone the students have been released. He did not confirm how many students were released.

       Armed groups carrying out kidnapping for ransom are blamed for a series of raids on schools in northern Nigeria in recent months, abducting more than 1,000 students since December.

       Abubakar Garba Alhasan, whose seven children are held by the gang, said the students were on their way to the capital city in Minna. "They are released now," he said.

       (Reporting by Maiduguri newsroom; Writing by Chijioke Ohuocha; editing by Grant McCool)