At least three Palestinian policemen have been killed in suicide attacks on two police checkpoints in Gaza.
Security sources say the attacks are believed to have been carried out by suicide bombers belonging to the extremist Islamic State militia.
The attacks came after Hamas’s operation against Gaza-linked militants in Gaza.
Security sources told the BBC that one of the attackers on Tuesday was also in the custody of the attacker.
Emergency has been imposed in Gaza since the attacks, while security forces are on high alert.
The first attack was carried out by a motorcycle near a check post, killing two police officers and injuring one Palestinian.
Within an hour of the attack, another attack killed another officer and injured several others, the Hamas Interior Ministry said.
Security forces have deployed hundreds of troops to the main highway in the Gaza Strip following the attacks.
Hamas has been facing internal resistance from radical Islamist fighters, including radical Islamist elements, at times.
Hamas took control of Gaza from President Mahmoud Abbas during the civil war of 2007.