KADUNA, Nigeria, Sept 7 (Reuters) - Gunmen invaded a village in the northern Nigerian state of Kaduna and kidnapped 18 residents including seven children, a community leader said on Tuesday, the latest in a wave of mass abductions disrupting every aspect of life in the region. Gangs of ransom seekers have been kidnapping children from their schools, villagers from their homes and travellers from their vehicles across northwest Nigeria since last December. Mallam Suleiman Keke, a community leader in the village of Keke B on the outskirts of the state capital Kaduna, said gunmen on motorbikes arrived late on Monday night and went from house to house seizing children and their parents. "It was a terrifying experience for us," he said, adding that the kidnappers had not yet sent a ransom demand. A spokesman for the police in Kaduna State could not be reached for comment. Kaduna is among several states that have adopted measures to try to curb the attacks, such as banning the sale of fuel in jerry cans and the transport of firewood in trucks to stop armed gangs who travel by motorbike and camp in remote areas. In Zamfara State, farther to the northwest, authorities have ordered a telecommunications blackout while the military tries to tackle the gangs. Large numbers of children have dropped out of school for fear of being kidnapped, and in some cases boarding schools have been ordered to turn themselves into day schools, with pupils hastily reassigned from one school to another. Food is often hard to come by, in part because farmers cannot reach their lands in remote areas for fear of the gangs, while families are being kept apart because people are afraid of travelling by road to visit relatives.