Hamas has claimed that it captured the mastermind behind the suicide bombings in Gaza last week that killed three policemen and wounded several more. According to the Palestinian news agency Sawa, Salah Bardawil, a senior Hamas official, said that the arrest of the unidentified figure after a large manhunt was a "decisive blow" against those who opposed the group in Gaza. The two blasts on Tuesday last week stuck police checkpoints. It is not known who was responsible for the attacks. Hamas faces opposition from factions sympathetic to ISIS and is locked in a rivalry with the Palestinian Authority. ISIS has an affiliate in the Sinai Peninsula, an area that borders Gaza to the south. Some officials said those behind the attacks could be collaborators with Israel. Working with Israel against Hamas is a crime punishable by death in Gaza. "The hand of treachery and treason that carried out the crime of bombings will be chopped off from the roots," Hamas said. The explosions led Hamas to declare a state of emergency across the territory, home to about 2 million Palestinians. Israel denied that it had any role in the bombings. It has fought three wars with Hamas since 2008. Factions unrelated to Hamas have been accused of launching rockets into Israel with the aim of shattering a fragile truce between the two. The deadly blasts are also reminiscent of previous rounds of bloody infighting between Hamas and more radical groups that consider Gaza's rulers to be too moderate. Hamas chief Ismail Haniyeh said that Gaza could cope with such incidents. "We are certain things will be controlled and all sides involved in these bombings will be held accountable," he said.