An early morning bomb explosion on Sunday hit a Nigerian police mobile base in northern Gombe State as casualties are feared, a competent source told Xinhua. The source said that a powerful explosion rocked \"Mopol 34\" in Gombe state at about 4 a.m local time, saying casualties are feared. Some unknown gunmen suspected to be members of the dreaded Islamist group Boko Haram hurled a bomb at the mobile police base leading to the explosion, according to the source. \"Two building and seven operational vehicles were badly burnt, \" the police source told Xinhua. But the police at the scene said they could not confirm the figure at this stage.