* Hundreds have been killed in "Middle Belt" violence
* Attacks not linked to Boko Haram insurgency
* Land disputes underlie ethnic and sectarian tensions (Adds witness accounts)
By Isaac Abrak
KADUNA, Nigeria, March 16 (Reuters) - Gunmen shot, hacked and burned to death at least 100 people and razed homes in central Nigeria, a region riven by disputes over land, religion and ethnicity, local officials and witnesses said on Sunday.
Police confirmed the raids by Fulani herdsman at around 11 p.m. on Friday on three villages in Kaduna state, but declined to give a death toll.
Hundreds have been killed in the past year in clashes pitting the cattle-herding and largely Muslim Fulani people against mostly Christian settled communities like the Berom in Nigeria's volatile "Middle Belt", where its mostly Christian south and Muslim north meet.
"I came back from the market and there were bullets flying all around the village," said Pius Nna, 64, of Ungwan Gata village. He escaped by jumping across an open well and fleeing into the bush.
"I saw three people running into my house to take refuge. They were macheted to death before my eyes," he said, adding that he saw a Fulani neighbour directing the gunmen where to go.
The unrest in central Nigeria is not usually linked to the insurgency in the northeast by Boko Haram, an al Qaeda-linked group which wants to impose Islamic law in northern Nigeria.
However, analysts say there is a risk the insurgents will try to stoke central Nigeria's conflict. Although most of the Islamist sect's attacks are contained further north, it did claim a 2011 Christmas Day bomb attack at a church in the central city of Jos.
"We are still picking bodies out of the bush but so far there are more than 100 killed," said Daniel Anyip, vice chairman of the Kaura local government authority.
Andrew Kazah, another local councillor, said at least 96 had been killed, but that the toll was likely to go up.
HISTORY OF CLASHES
Human Rights Watch in December said sectarian clashes in the religiously mixed central region had killed 3,000 people since 2010, adding that Nigerian authorities had largely ignored the violence, an accusation they denied.
Though it sometimes takes on a sectarian character, the violence is fundamentally driven by decades-old land disputes between semi-nomadic, cattle-keeping communities such as the Fulani and settled farming peoples such as the Berom, both often armed with automatic weapons.
Bulus Mallam, 49, said he saw Fulani herdsman pour petrol on the roof of his house in Ugwar Sankwai and set it ablaze. His wife and 22 children and grandchildren managed to escape as the attackers were concentrating on looting mattresses, palm oil and maize.
"I thank God no one was killed in my household. My brother was not so lucky. They burned him and 40 people hiding in his house alive," he said.
Of the village's 200 inhabitants, at least 57 were killed, he said.
Nigeria is Africa's most populous nation with almost 170 million people, split roughly equally between Christians and Muslims and around 250 different ethnic groups who mostly live peacefully side-by-side.
But the central region has been a tinderbox for decades.
Far from economic centres or oil fields in Africa's second-biggest economy and top oil producer, the violence rarely captures the attention of Nigeria's elites, whom nonetheless occasionally use it for political ends.
Post-election violence in 2011 in Kaduna state resulted in around 800 deaths in three days, in what was triggered by northern Muslim grievances about political alienation but quickly turned into ethnically-driven killing. (Writing by Tim Cocks; Editing by Alison Williams and Robin Pomeroy)