Algiers - A suicide bomber killed two Algerian policemen on Thursday, including one who threw himself on the attacker whose explosives belt then detonated, state media said, citing the security services.In the second such attack this year, the attacker tried to enter the police headquarters in the Tiaret region, 350km southwest of Algiers, but was blocked by the officers, the official APS news agency reported.The agency said the "terrorist" had been carrying a weapon as well as wearing an explosives belt."The policemen on duty responded quickly, and one of them, in an act of bravery, threw himself on the assailant at the entrance of the headquarters and lost his life" as the belt exploded, killing both men, the national security directorate said, quoted by the agency.The other police officer died of his wounds after the bomb attack, for which there was no immediate claim of responsibility.In February, a policeman foiled an attempted suicide attack on a police station in the eastern city of Constantine by opening fire on the approaching assailant and triggering the explosives belt he was wearing.That attack was claimed by the Islamic State (ISIS) jihadist group."Vigilance seems to have been stepped down. We had a feeling that this was coming," a former security services official said after Thursday's bombing, asking not to be named.He told AFP it was probably the work of Algerian members of ISIS who had fled countries where the jihadists were under increased military pressure. Algerians had hoped that a 2005 peace and reconciliation charter would turn the page on a 1991-2002 civil war between Islamists and security forces that cost 200 000 lives.But Islamist groups remain active in some areas, especially in southern and eastern Algeria, mostly targeting the police and army.Dozens of armed Islamists have been killed in sweeps by Algerian security forces this year.The deadliest post-civil war clash dates back to March 2013, when Al-Qaeda-linked militants stormed the In Amenas gas plant in southeast Algeria, resulting in 40 hostages and 29 assailants killed in a rescue operation by Algerian troops.