Gunmen have opened fire on a church service in the northeast Nigerian village of Attangara, killing nine people, police and a witness said.
The village is in the Gwoza hills, near the Cameroon border, and a stronghold of armed group Boko Haram which has killed civilians on an almost daily basis since stepping up its campaign of violence earlier this year.
"As we were holding service, we started hearing gunshots and everybody fled, some through the windows, and ran into the bush," resident Matha Yohana said of Sunday's attack.
A police source said nine were killed in the assault.
"More than 10 of them were riding motorcycles and one car," she said, adding some local vigilantes had pursued the attackers, killing four of them and arresting three.
Nigeria's military said on Monday it had arrested a suspect it believed was behind a bomb attack that killed 18 people watching football on television in the northeast the previous day.
There has been no claim of responsibility for the blast that also wounded 19 people in Kabang town in Adamawa state, another stronghold of Boko Haram.
"A key suspect in the terror bomb explosion that rocked Kabang community in Mubi, Adamawa state... has been arrested by troops who cordoned [the area in swift response to the explosion," defence spokesman Chris Olukolade, a brigadier general, told the Reuters news agency.
The toll was 18 killed, 19 wounded, he added. Initial reports had put the death toll at 14.
Thousands of people have died since Boko Haram launched an uprising in 2009.
Meanwhile, police in the Nigerian capital Abuja banned protests over missing schoolgirls, saying they could be hijacked by "dangerous elements".
"As the FCT (Federal Capital Territory) police boss, I cannot fold my hands and watch this lawlessness," police commissioner Joseph Mbu was quoted by the state-owned News Agency of Nigeria (NAN) as saying on Monday.
"Information reaching us is that too soon, dangerous elements will join groups under the guise of protest and detonate explosives aimed at embarrassing the government."
At least 530 civilians have been killed since April 14 the day the schoolgirls were abducted, according to a Reuters count.