GAZA — Two suicide bombers hit Hamas police checkpoints in Gaza City late Tuesday, killing three police officers and wounding three other Palestinians, security officials said on Wednesday, in an uncommon attack from within the territory.

Two of the officers were part of the armed wing of Hamas, the Islamist militant group that governs Gaza. The group has been mostly engaged in cross-border clashes with the Israeli military. But at times it has faced internal opposition from more stringent Islamist militants aligned with Al Qaeda or the Islamic State.

Eyad al-Buzom, a spokesman for Hamas’s Interior Ministry, said in a local TV interview that two suicide bombers had carried out the attacks at the checkpoints. He said that security forces were investigating the explosions and that a number of suspects had been arrested.

Hamas’s intelligence was able to identify the attackers, officials said, but their names were not immediately revealed. No further details were released.