An estimated 344 schoolboys abducted in northwest Nigeria last week have been released, a local official in Katsina state said on Thursday. "We have 344 students, they are in currently in Zamfara undergoing checks. We are grateful to God they have been released," Ibrahim Katsina, a security aide to the governor told AFP. Earlier, a presidential aide said the schoolboys had been freed, but it was unclear was how many were released amid ongoing uncertainty over the number taken in the first place. abu-lhd/har