Officials in Turkey say police have detained over 500 people since Monday because of their suspected ties to Kurdish militants. Members of the Peoples’ Democratic Party (HDP), parliament's second largest opposition group, are reported to be among the detained. Police launched raids across the country after a group called the Kurdistan Freedom Falcons claimed responsibility for two bomb attacks. Turkish officials accuse the group of having ties to the Kurdistan Workers’ Party (PKK), which is banned in the country. The bombs exploded late Saturday near a sports center in Istanbul. The explosions killed at least 44 people and wounded more than 150 others. Officials say the blasts targeted security officials. The government has often accused the HDP of being an extension of the PKK. The top HDP official was among those arrested in Ankara. Other leaders of the party, the second largest opposition group in parliament, are in jail over reported ties to the PKK. The bombings come after months of fighting between Turkish forces and Kurdish militants. The Kurdistan Freedom Falcons claim the bombings were meant to answer state violence in the southeast, reported the Associated Press.