Unidentified attackers have fire-bombed a mosque in northern Yemen, injuring about 30 people, officials have said.
Yemeni security forces said on Saturday they had arrested a man apparently responsible for the attack.
Two assailants burst into the mosque during Friday prayers, spraying worshippers with petrol before setting them alight, Yemeni news sources said.
At least six people appear to have suffered serious burns and were taken to hospital in the capital, Sanaa.
Others were treated in local hospitals.
The attack took place in Amran province, to the south of an area where government forces are battling against Shia Muslim militants.
But there was no immediate sign of any connection to the rebels, who usually attack security forces and do not regularly operate in Amran.
It was not immediately clear if the mosque was used by Sunni or Shia worshippers.
Yemen's 26 September newspaper said the attack was considered "strange" by Yemeni officials.
"Security authorities are investigating to identify the assailants and the motives of this criminal act," the official Saba news agency quoted Amran's Governor Taha Hajar as saying.