Nearly 30 students kidnapped by gunmen from their college two months ago in northwest Nigeria have been freed, local state authorities said on Wednesday. The abduction of the students from a college of forestry mechanization in Kaduna state in March was one of a series of mass kidnappings to hit schools and universities in Nigeria since late last year. Ten of the 39 students initially kidnapped were found by security forces in the weeks following the attack. But the whereabouts of the remaining 29 had been uncertain. "The Kaduna State Police Command has reported to the Kaduna State Government, the release of the remaining students of the Federal College of Forestry Mechanization," local state security official Samuel Aruwan said in a statement. The statement did not give any details about how the students were released or their condition. Heavily armed criminal gangs have become an increasing security threat in northwest and central Nigeria, pillaging villages, raiding cattle and kidnapping for ransom. Recently they have turned their focus to rural schools and universities, where they kidnap students or schoolchildren. Kidnap victims are usually released shortly after during negotiations with local authorities, though state officials always deny any ransom payments have been made. amu/pma/kjl