KADUNA/KANO, Nigeria (Reuters) - Suspected Islamist gunmen have launched a series of gun and bomb attacks in a remote town along Nigeria's border with Cameroon, killing at least 25 people, police said on Saturday.
The gunmen carried out four simultaneous assaults on Ganye in Adamawa state on Friday, opening fire on a bar, a bank, a prisoner warder and separately attacking a prison, Mohammed Ibrahim, police spokesman for the western Adamawa state said.
"Twenty five people were killed in total in four different simultaneous attacks by gunmen in Ganye," Ibrahim said.
Members of insurgent group Boko Haram were the prime suspects, he said. Violence by Islamist insurgents in northern Nigeria is on the rise again after a brief lull.
Three bombs exploded in the north's main city of Kano on Saturday, Kano state police spokesman Magaji Majiya said by telephone.
One of the bombings was a suicide attack, but did not claim any lives apart from those of the bombers. However, a remote control bomb targeting a joint military and police checkpoint wounded several police, he said.
A separate gun attack in the city's Dakata area killed one person on Saturday, he said.
Majiya said four people had been arrested in connection with the attacks.
Islamist insurgent group Boko Haram, factional offshoots of it and related criminal gangs have overtaken militancy in the oil-producing southeastern Niger Delta region as the main threat to the stability of Africa's top energy producer.
On Monday, a bomb blast targeting a bus park in an area of Kano mostly inhabited by southern Christians killed at least 25 people and wounded 65.
Boko Haram, which wants an Islamic state in religiously mixed Nigeria, has killed many hundreds in gun and bomb attacks since it intensified its insurgency two years ago, including 186 people in a strike on Kano in January 2012, its worst single attack.
Its fighters operate across northern Nigeria and in neighboring states Chad, Niger and Cameroon.
On Monday, an audio tape emerged of a man saying he was the father of a family of seven French tourists kidnapped by Boko Haram militants. He read out a threat by them to increase kidnappings and suicide bombings in Cameroon, if authorities there detained more of the group's followers.
The French family was kidnapped from north Cameroon last month but is believed to be being held in Nigeria.
Increased kidnappings of Westerners has raised alarm that Nigerian Islamists - under the influence of other groups in the region like al Qaeda's north African wing - are turning their sights towards Western targets.
(Reporting by Isaac Abrak and Chukwuemeka Madu; Writing by Tim Cocks; Editing by Sophie Hares)