Cameroonian troops pursuing Boko Haram fired rocket-propelled grenades indiscriminately that killed a family of four, then shot and killed two other civilians, trapped Nigerian villagers said Tuesday.

It is the latest of several reports accusing the military of neighboring Cameroon of killing scores of Nigerian civilians and razing villages in an apparent attempt to create a no-go zone along the border.

Cameroon's government has denied previous similar charges, which come amid rising tensions between Nigeria and its neighbors over the Islamic uprising that has spilled over Nigeria's borders.

Muhammad Abba, deputy commander of a civilian self-defense group, said relatives telephoned him Tuesday to describe how one grenade exploded through the grass roof of a hut and killed a family of four in the northeastern village Ashigashiya on Monday.

Then Cameroonian soldiers dragged away two elderly men and shot them on the outskirts of the village, Abba said.

He said villagers have been trapped for weeks between hostile Cameroonian troops and an area where Boko Haram is operating.

There was no way to independently verify his report.

The first such story came from refugees who said Cameroonian soldiers on Nov. 30 killed about 150 people, stole livestock and set huts ablaze along a 150-kilometer (95-mile) stretch of the border. Hundreds of refugees have arrived with similar reports.

Nigerian government officials have not responded to requests for comment, instead warning local press to be "patriotic." Cameroon said its troops were deployed with Nigerian soldiers in the fight against Boko Haram.

The raids began days after Nigeria refused requests from neighboring countries to evacuate border villages and create a buffer zone where troops could shoot anything that moved to prevent incursions by Boko Haram, according to a diplomat familiar with negotiations.

Nigerian troops also have been accused of atrocities in the six-year uprising that has killed 20,000 people.