Hamas rulers in the Gaza Strip said Tuesday that a man suspected of killing an Italian pro-Palestinian activist in the territory committed suicide during a tense police standoff.

The suspect, a Jordanian citizen, shot himself after he hurled a grenade at two of his partners, critically injuring one of them, the Hamas-run Interior Ministry said in a statement published on its website.

Three policemen were injured during an exchange of fire, the statement added.

Hamas police said armed officers surrounded a house in the Nuseirat refugee camp in the central Gaza Strip in which three Islamist Salafists had taken shelter.

Police cordoned off the area and evacuated scores of houses. Clashes between police and the armed Salafists lasted almost two hours.

A police official who spoke on condition of anonymity said police tried to resolve the situation peacefully, but the other side continued firing at soldiers and mediators.

The Interior Ministry on Monday posted names and photos on its website of suspects in the killing of Italian activist Vittorio Arrigoni and indicated that it had begun a manhunt.

The body of Arrigoni was discovered in an abandoned house just hours after a radical Islamist group with links to Al Qaeda announced that it was holding him in exchange for the release of its leader, who is being held in a Hamas prison.

It was the first abduction of a Westerner in Gaza since 2007. It is also the only instance of such a kidnapping victim being slain.