Gunmen have attacked a police station in northern Nigeria\'s Jigawa state, killing a teenage girl and wounding an officer in the first such incident since the president\'s state of emergency decree. \"The gunmen shot indiscriminately into the police station and engaged our men in a shootout, killing a teenage girl trying to flee and wounding a policeman,\" Jigawa state police commissioner Hashimu Argungu said of the attack late Tuesday. \"They threw an explosive into the police station but it did not detonate, which saved the police station from being destroyed, although its walls were riddled with bullets from the attack.\" Argungu said an investigation was ongoing and he could not yet say who was behind the attack. Scores of such attacks in Nigeria\'s north have been blamed on Islamist group Boko Haram. President Goodluck Jonathan declared a state of emergency last weekend in parts of four states hard hit by attacks blamed on Boko Haram. The decree included parts of Yobe state, which neighbours Jigawa, as well as areas of Borno, Niger and Plateau states. Some have expressed fears that Boko Haram would shift its attacks to areas not affected by the state of emergency. Tuesday night\'s attack targeted a divisional police station in the town of Birniwa on the border with Yobe. Jonathan\'s declaration came in response to scores of attacks attributed to the group, particularly bombings at Christmas that killed 49 people, most of them in a gruesome blast at a Catholic church as services were ending. While Boko Haram has been carrying out increasingly deadly attacks for months, including an August suicide bombing of UN headquarters in Abuja that left 25 dead, the Christmas violence sparked intense fear and outrage. Muslims have frequently been victims of Boko Haram attacks, most of which have occurred in northeastern Nigeria, but the Christmas Day bombings particularly targeting churches set off fears of retaliation from Christians. Nigeria, Africa\'s most populous nation and largest oil producer with 160 million people, is roughly divided between a mainly Muslim north and predominantly Christian south. On Sunday, a purported spokesman for Boko Haram warned that the group would confront soldiers and threatened Christians living in the country\'s north. The threat from the purported spokesman gave southerners living in Nigeria\'s north three days to leave the region in the wake of Jonathan\'s state of emergency decree. Nigerian authorities said they did not believe militants would follow through on the ultimatum, but added that they were taking no chances. While the purported spokesman, Abul Qaqa, has claimed to speak on behalf of Boko Haram numerous times in the past, the group is believed to have a number of factions and others have also claimed to speak for it.