MAIDUGURI (Reuters) - Suspected Boko Haram gunmen have shot dead 29 farm workers as they tilled their fields in a village in the remote northeast, a police source said on Thursday.

The source at police headquarters for Borno state, in the heart of the insurgency, said around 10 more people had been wounded in Wednesday's attack on Chukku Nguddoa, in which most of the village, including its grain store, were razed.

In the past two months, Boko Haram militants have stepped up their five-year-old campaign to carve an Islamic state out of religiously mixed Nigeria. They have relentlessly targeted civilians, especially in the northeast, whom the military seems helpless to protect.

Bomb attacks are growing more sophisticated, including two on the capital Abuja last month, and massacres of villagers in the area where Boko Haram is based are an almost daily occurrence.

Militants killed 17 people in Alagarno village on Tuesday and razed several houses to the ground.

Hours earlier, a double bomb blast in the central Nigerian city of Jos had killed 118 people, according to the emergency services, while men on motorbikes killed nine people in a raid on the nearby village of Shawa on Monday.

While authorities suspect Boko Haram of carrying out all these attacks, there have been no claims of responsibility.

The well armed militant group has no direct line of communication with the Western press and its purported leader, Abubakar Shekau, claims only occasional attacks - including the abduction of more than 200 schoolgirls from a village last month - through videos circulated to local journalists.


Some of the 80 U.S. troops deployed for a mission aiming to rescue the school girls have already arrived in ChadPentagon spokesman Army Colonel Steve Warren said on Thursday.

The Islamists have killed thousands since launching an uprising in 2009, mostly civilians, and a year-old military offensive meant to wipe them out appears only to have exacerbated the slaughter.

But the abduction of the schoolgirls has put the group in world headlines as never before, as a global campaign to get them freed has persuaded Western powers to take action in support of Nigerian forces.

Nigerian teachers went on strike and staged rallies nationwide on Thursday in protest against the kidnappings, as well as the killing of 173 teachers by the insurgents over the years.

President Goodluck Jonathan and the military were heavily criticized in Nigeria for the slowness of their reaction to the mass abduction, and last week Nigeria accepted help from the United States, Britain, France and China to find the girls.

As well as deploying personnel, the U.S. military has been flying unmanned surveillance aircraft over remote areas of northeast Nigeria for two weeks, and last weekend the Pentagon struck an agreement to enable it to share intelligence directly with the Nigerian government.

Yet a rescue mission would be fraught with danger. Little has been said in public about the girls' possible whereabouts or whether any negotiations are going on behind the scenes to free them.