Dozens were killed in a spate of coordinated gun and bomb attacks in the northeastern Nigerian city of Damaturu on Friday, leaving the city almost deserted and bodies piling up in local morgues, witnesses said on Saturday.

Suspected Boko Haram gunmen raided the city and the nearby village of Potiskum, both in northeastern Yobe state, on Friday evening and engaged in several hours of running gun battles with security forces.

This place was like a war zone last night. There is no single policeman on the street now, the attacks destroyed mosques and churches, I have seen many injured persons in the hospital, said local Damaturu artisan Benard Ogbeifun.

There were dozens of dead bodies, and no vehicles on the road. I'm staying in my shop and praying.

The attacks followed multiple bomb blasts in nearby Maiduguri, making Friday one of the worst days of violence in the northeast since Islamist sect Boko Haram launched an insurgency against Nigerian authorities in 2009, vowing to impose sharia law across the country.

The fighting in Damaturu killed dozens, witnesses said. Nine security forces were amongst the dead, a military source said. Militants bombed churches, mosques and police stations.

Another witness, Umar Gambo, said he had seen several dozen dead bodies at the local morgue.

The streets are deserted. I have lost count of dead bodies, but ... I saw at least 80 dead bodies in the mortuary. There is no high presence of security on the streets and two banks were bombed, he said. I can't understand why all this madness.

A security source in Maiduguri, the heart of the Boko Haram insurgency, said at least seven police and two soldiers had been killed in the fighting in Damaturu. He had no figures for civilian casualties.

TRIPLE BOMBING

Earlier in the day, a triple suicide bombing of military headquarters in Maiduguri, northeast Nigeria's biggest city, and three roadside bombs in different parts of it, wounded at least seven. The blasts all went off shortly after Friday prayers.

Boko Haram says it wants sharia law more widely imposed across Nigeria. It draws much of its support from unemployed youths in the remote, economically deprived north.

The group appears to be growing in sophistication and security analysts believe it has made links with al Qaeda's north African affiliate.

A suicide car bomb attack against the United Nations' Nigeria headquarters in Abuja killed 26 people.

Umar Mairiga, a Nigeria Red Cross official at the country headquarters, said the aid agency had no confirmation yet on the death toll from Friday's violence, but was expecting to be able to tally it later.

(Reporting by Mike Oboh in Kano and a Maidurugi correspondent; Writing and additional reporting by Tim Cocks in Lagos; Editing by Sophie Hares)