Nairobi/Abuja, July 29 (DPA) Nigerian security forces Wednesday laid siege to the compound of an Islamist leader whose followers have been battling police for four days.

Over 150 people have died since Sunday, when Boko Haram, a group often called as the Nigerian Taliban, launched a series of attacks on police stations across northern Nigeria.

The army shelled the compound of Mohammed Yusuf, the group's leader, in the town of Maiduguri, Borno state, Tuesday. Gunfire was exchanged throughout the night and into Wednesday morning.

Colonel Ben Ahanotu, the officer in charge of the Nigerian Army's assault on Yusu's home, told the BBC that at least 250 militants were protecting the compound, which serves as Boko Haram's base.

Nigeria, Africa's most populous nation with around 150 million inhabitants, is split between the Muslim north and the Christian and animist south.

Boko Haram, which was formed in 2002, wants to impose Islamic law (Sharia), across the country and is also opposed to Western education.

The group launched its first attack on a police station in Bauchi, sending around 70 men armed with automatic weapons and grenades into the fray.

The police repelled the initial attack, killing dozens of militants, but the violence then spread.

Over 100 people were reported killed in Maiduguri and in Potiskum, Yobe state, militants set fire to a police station and murdered one of the firefighters attempting to tackle the blaze.