Boko Haram gunmen have killed more than 140 people in three separate attacks on mosques and villages in Nigeria's northeast Borno State.
A government official said that several mosques were attacked in the town of Kukawa on Wednesday night, with at least 97 men, women and children among the victims.
Two other villages were also attacked, with women and children again among the dead.
On Thursday, a suicide attacker also blew up a military checkpoint near Maiduguri, killing at least four people.
Al Jazeera's Yvonne Ndege, reporting from Abuja, said Boko Haram had embarked on a "really bloody 72 hours in Borno State", and the worst of the attacks had taken place in Kukawa, 180km northeast of Maiduguri, the biggest city in northeast Nigeria.
Officials said the people of Kukawa were in several mosques, praying ahead of breaking their daylong fast, when the fighters attacked.
"We are being told that Boko Haram fighters arrived in seven cars and on nine motorcycles in the town before embarking on their attack, and that over 1,000 Nigerian soldiers were in Kanwa, about 11km away but didn't come to the rescue," our correspondent said.
Officials in Kukawa said some fighters then broke into people's homes, killing women and children as they prepared the evening meal.
"Some witnesses have described awful scenes," our correspondent said.
"A witness called Kolo said they killed men and young boys in the mosques and then proceeded to burn the corpses they had killed. They then indiscriminately attacked women and children who were at home."
News of Wednesday night's gruesome incident only came to light on Thursday, our correspondent said.
The Kukawa attack came a day after the group attacked the village of Mussaram 35km away and killed another 48 men and boys.
On Tuesday night, Boko Haram invaded Mussaram, ordered men and women to separate and then opened fire on the men and boys, witnesses said.
"A total of 48 males died on the spot while 17 others escaped with serious injuries," said Maidugu Bida, a local vigilante group commander.
The spate of attacks follow a directive from the Islamic State of Iraq and the Levant (ISIL) group for fighters to increase attacks during Ramadan.
Boko Haram this year became ISIL's West African franchise.
The Nigerian group, whose birthplace is Maiduguri, often defiles mosques where it believes imams espouse too moderate a form of Islam.
Source: Al Jazeera and agencies