Suspected Boko Haram militants have launched an attack on a village near the north-eastern Nigerian city of Maiduguri, killing about 45 people.
The attackers told villagers they had come to preach before firing on a crowd that gathered, survivors told the BBC.
Separately, officials say up to 200 may have been killed in a wave of attacks in villages in the region this week.
Militants have frequently targeted remote areas since emergency rule was imposed a year ago in the north-east.
Nigeria's government has been facing growing pressure both at home and abroad to do more to tackle Boko Haram since militants kidnapped more than 200 schoolgirls in April.
The group has waged an increasingly bloody insurgency since 2009 in an attempt to create an Islamic state in Nigeria - and thousands of people have died in their attacks and the subsequent security crackdown.
The attack on the village of Bardari, near the University of Maiduguri on the outskirts of the city, took place late on Wednesday.
The militants entered the village telling people to gather to hear them preach, but then turned their guns on the crowd.
Timeline of recent attacks
- Sunday - Tuesday: At least 200 people reported killed by gunmen in military dress in a wave of attacks on six villages in the Gwoza area of Borno state
- Wednesday: Some 45 people killed by militants posing as preachers in Barderi village near Maiduguri, capital of Borno State
- Thursday: Two killed in gunfire exchange in village of Madagali, Adamawa state
Police sources told Reuters news agency that the attackers then fled across a river, setting fire to houses in a nearby village.
Boko Haram flags
It follows an attack on Attagara village in the remote Gwoza area of Borno state on Tuesday, when gunmen dressed in military uniforms convinced residents that they had come to provide protection after an earlier attack on Sunday.
One witness, quoted by the Associated Press agency, said the militants had gathered people together in the centre of the village before they began "to fire continuously for a very long time until all that had gathered were dead".
Attagara is one of six villages in the area where a total of at least 200 people are believed to have been killed in recent days.
The local MP, Peter Biye, told the BBC that it was impossible to know exactly how many people had died, because everyone who could do so had fled into the nearby hills and there was no-one to count the bodies.
Despite repeated requests, Nigerian soldiers had not deployed to the area, Mr Biye said.
The villages affected are near the Mandara Mountains, close to the border with Cameroon where Boko Haram is known to operate.
There are reports that the group's jihadist flags are flying in several villages in Gwoza.
Who are Boko Haram?
- Founded in 2002
- Initially focused on opposing Western education - Boko Haram means "Western education is forbidden" in the Hausa language
- Launched military operations in 2009 to create Islamic state
- Thousands killed, mostly in north-eastern Nigeria - also attacked police and UN headquarters in capital, Abuja
- Some three million people affected
- Declared terrorist group by US in 2013
In the early hours of Thursday morning, another attack reportedly took place in Adamawa state, one of the three states under emergency rule.
Residents of the village of Madagali told the BBC Hausa Service that over three hours, suspected Boko Haram militants exchanged fire with security forces, burnt down the administrative buildings and a church, and killed two people.
After they had left, the air force bombed the surrounding area and three people died, residents added.
A new report by the Internal Displacement Monitoring Centre and the Norwegian Refugee Council says 3,300 people have been killed by Boko Haram this year alone.
Meanwhile, the UK government has announced that it will host a ministerial meeting about northern Nigeria's security in London on 12 June - to follow on from last month's summit in Paris about tackling Boko Haram.
"Since the appalling abductions of over 200 schoolgirls in Chibok by Boko Haram, the international community has worked together closely to support Nigeria in the fight against terrorism," UK Foreign Secretary William Hague said in a statement.