Nigeria street vendor
A market in Maiduguri was targeted by Boko Haram

Tighter security in Nigeria ahead of Easter celebrations has failed to stop the slaughter of seven people by gunmen believed to belong to the Islamic extremist group Boko Haram.

Police said that members of the Salafi Islamist sect opened fire on a crowded marketplace in Maiduguri, northeast Nigeria. The attack took place in an area protected by federal troops, witnesses and police said.

Maiduguri is often described as Boko Haram's spiritual home. It was where the group was created a decade ago.

Authorities had boosted security amid fears that the Christian holiday period would be used for more attacks.

Borno state police spokesman Samuel Tizhe told Associated Press that seven civilians had been killed. Soldiers dispersed civilians but were unable to stop the gunmen, witnesses said.

The attack appears to have specifically targeted traders belonging to the Igbo ethnic group, residents insisted. They said the gunmen opened fire on an electronics salesman and then headed further into the market, killing other Igbo traders.

Nigeria's central government is struggling to clamp down on the sect.

Soldiers killed three suspected members in a shootout in Kano on 3 April, Lt Iweha Ikedichi said, thwarting a plan to carry out a fresh set of attacks in the city.

In January, coordinated bombings and shootings in Kano killed at least 185 people.

The attack in Maiduguri shows that Boko Haram remains fiercely defiant. The group has rejected government efforts to enter indirect peace talks.

Boko Haram, whose name means "Western education is sin" wants the introduction of Sharia law across Nigeria - even in Christian areas.

The sect is divided into cells independent of one another making it extremely difficult to predict where and when they will next launch an attack.