Islamabad , Pakistan ( CNN ) -- At least 11 people have been killed and dozens wounded in a suicide attack Monday on a court building in the Pakistani capital , authorities said . Two militants threw hand grenades , fired guns and then blew themselves up at the district court building , said Sikander Hayat , inspector general of Islamabad police . Another police official , Jamil Hashmi , said that there were other armed attackers who opened fire and then left the scene . Police are still in the process of establishing exactly what happened , he said . Witnesses at the court building told CNN they saw two men firing indiscriminately at people . Attacks of this nature are rare in Pakistan 's heavily policed capital . The Pakistan Institute of Medical Sciences , a complex that includes a hospital , reported the death toll of 11 and said 39 people were wounded in the attack . The dead included a judge , authorities said . The court building is in an upmarket residential district in central Islamabad . The area around the courts includes supermarkets , restaurants and coffee shops . A little-known organization calling itself Ahrar Ul Hind claimed it had carried out the attack . It targeted the courts because it considers them to be un-Islamic , said Asad Mansoor , a spokesman for the group . In a statement last month , Ahrar Ul Hind said that it had had ties with the Pakistani Taliban , but that the relationship had broken down because of the Taliban 's focus on Pakistan 's tribal areas . Ahrar Ul Hind claims it wants to impose Sharia , or Islamic law , in Pakistan , India and around the world . It says it aims to achieve its goal by carrying out attacks on cities . The Pakistani Taliban , which on Saturday declared a month-long cease-fire , denied any involvement with the Islamabad attack Monday . Shahidullah Shahid , a spokesman for the extremist group , said that the cease-fire was still in effect and that action would be taken against any faction that tried to break it . Asked last month about Ahrar Ul Hind , Shahid claimed the Taliban knew nothing about the organization . Attack targets polio workers in Pakistan , kills 11 . CNN 's Sophia Saifi and Saima Mohsin reported from Islamabad , and CNN 's Jethro Mullen wrote from Hong Kong . Journalists Adeel Raja , Saleem Mehsud and Zahir Shah Sherazi contributed to this report .
NEW : A little-known group calling itself Ahrar Ul Hind claims responsibility . Two militants throw grenades , fire guns and then blow themselves up , police say . The attack on a court building in central Islamabad wounds at least 39 people . A judge is among the 11 people reported dead by medical officials .