Heavily-armed unidentified gunmen today made an audacious bid to force their way into the Pakistan Army's Headquarters in Rawalpindi, sparking a raging gunbattle which left all four attackers and some soldiers dead. The attempt by the gunmen shortly before noon was foiled as the army brought in commandos and helicopters to overpower the attackers, who drove up in a white van to the entrance of the General Headquarters. TV news channels reported, an intense shootout broke out as troops tried to stop the attackers from entering the complex. Chief Military Spokesman Major General Athar Abbas told reporters that all four terrorists were killed, adding the situation is fully under control now. The heavily-armed terrorists, who were in a white van opened fire when they were challenged by soldiers at a check post. Mr Abbas said, there was some confusion as the attackers were wearing camouflage uniforms but they were all killed. No group claimed responsibility for the attack but observers said it appeared to be the handiwork of the Tehrik-e-Taliban Pakistan, which has vowed to target the Pakistani security forces to avenge the killing of its chief Baitullah Mehsud in a US drone attack in August. Earlier, witnesses told TV news channels that the terrorists had lobbed about five grenades at the Headquarters. The audacious attack was the third major assault in a week that came a day after a blast in NWFP capital Peshawar that left 50 people dead and over 120 injured. Prime Minister Yousuf Raza Gilani strongly condemned the attack in Rawalpindi, which is close to Islamabad. Security has been tightened across the country, especially in the federal capital, and for dignitaries like President, Prime Minister and Federal minister.