(CNN) -- Gunmen attacked a police station in northeast Nigeria early Sunday, killing two officers, the head of the police force in Yobe State said.
The attackers, believed to be connected to the militant Islamist group Boko Haram, fired a rocket into the police station near the state capital, said police Commissioner Patrick Egbuniwe. One of the officers was killed by the blast, the other came under fire while responding to the attack.
The gunmen fled after taking an injured member of their group with them. They had two cars, one of which was found abandoned and destroyed near the police station, Egbuniwe said.
Police are searching for the attackers and the second vehicle. Residents were asked to go about their day and resume "normalcy."
The attack follows a particularly volatile week in Nigeria, where a human rights groups accused Nigerian security forces of committing serious abuses as they try to crack down on Boko Haram. Amnesty International reported more than 30 people recently shot dead in Nigeria.
At the same time, Boko Haram, which seeks to impose a strict version of Sharia law in the Muslim-dominated northern part of the country, was blamed in the assassination of retired Maj. Gen. Muhammadu Shuwa.
In its report Thursday, Amnesty International condemned the increasingly brutal attacks carried out by Boko Haram since 2009, but said Nigeria's security forces "have perpetrated serious human rights violations" in their response. A military spokesman rejected the allegations.
CNN's Nana Karikari-apau contributed to this report.