* Death count from earlier attacks reaches 110 - leaders
* Fleeing villagers stranded, short of food - senator
* Boko Haram has killed thousands, targeting civilians (Adds analyst, quotes, Cameroon attack, background)
By Isaac Abrak and Lanre Ola
ABUJA/MAIDUGURI, Nigeria, June 8 (Reuters) - An explosion killed at least three people outside an army barracks in Nigeria's northeastern city of Gombe on Sunday, witnesses said, as local leaders reported the death count from a string of earlier attacks had reached 110.
No one claimed responsibility for the blast or last week's assaults but Islamist group Boko Haram has set off bombs and killed thousands in its five-year-old bid to carve out an Islamist state in the region.
"I heard a loud sound and then black smoke covering the place ... We saw soldiers moving bodies," Gombe trader Bello Kasuwankatako told Reuters.
Boko Haram - which dominated world headlines by kidnapping more than 200 schoolgirls in April - has fought back against an army offensive, piling political pressure on President Goodluck Jonathan and the military to end the carnage.
Leaders from Gombe's neighbouring state of Borno told journalists on Sunday they had now buried 110 bodies from attacks on nine villages early last week - giving the first detailed breakdown on the casualties.
"It was a great tragedy. There are still corpses lying in the bushes surrounding the communities. Many of our people that fled to the top of the hills during and after the attacks are still there and now stranded," said Ali Ndume, a senator representing southern Borno.
CIVILIANS EASY TARGETS
Boko Haram started off focusing on military and government targets alongside schools - seen as representing corrupt Western influence - churches, and Muslim leaders who do not follow its brand of Islam.
It has been increasingly turning its guns on civilians in recent months, particularly after locals started setting up vigilante groups to try and fight back.
Traditional leader Lawan Abba Kaka said they had buried 42 corpses at the village of Attagara, 24 at Aganjara, 20 at Agapalawa and smaller numbers at other settlements - all of them in the Gwoza hills near the border with Cameroon.
"The insurgents came and said they wanted to discuss something with us. They said we need to discuss some issues bordering on our differences in the communities but they opened fire on people who were gathered," said Kaka.
On Wednesday, gunmen rounded up more villagers outside Borno's state capital Maiduguri saying they were going to deliver a sermon, then opened fire, killing at least 42, said a police source.
"It seems they are moving to rural areas," Hannah Donges, a researcher at the Small Arms Survey, told Reuters. "They are easier targets ... It doesn't need sophisticated tactics. It makes them (Boko Haram) less predictable."
Suspected Boko Haram militants attacked a town in Cameroon's far north on Saturday but local security forces fought them off, killing at least two gunmen, Cameroon's government said. The militant group is also thought to be active in neighbouring Niger and Chad.
The kidnapping of the girls from a secondary school in Borno's town of Chibok triggered a national and international campaign under the Twitter hashtag #BringBackOurGirls, calling on the government to step its efforts to free them. (Writing by Andrew Heavens; Editing by Stephen Powell)