Gunmen have killed three people at an agricultural college in Nigeria's northwest Zamfara state and kidnapped 20 others, including 15 students, school officials said Monday.

"Unknown gunmen attacked the school around 10:00pm (2100 GMT) on Sunday," registrar Aminu Khalid Maradun told AFP. "They killed three people...and abducted 20, including 15 students." Another school official also confirmed the attack.