Israeli army troops arrested scores of Palestinians during an incursion into southern Gaza city of Kahn Younis yesterday afternoon, hours after the killing of four people in the offensive.

The Israeli operation started at midnight are still going on as the Israeli helicopters fired at a group of Islamic Jihad (Holy War) militants in al-Qarara neighborhood of eastern Khan Younis this afternoon, wounding three of them, local residents said.

They added that Israeli army took away tens of residents for interrogation amid the operation.

Witnesses said the detainees were moved by trucks towards the Israeli territories.

So far, the operation has killed four Palestinians, including two Hamas militants.

The first casualty was recorded three hours after midnight when helicopter gunships killed a Hamas militant.

The Israeli sniper gunfire led to the other three deaths, including another Hamas member and his mother.

Meanwhile, a number of injuries were left bleeding as the heavy Israeli fire prevented the ambulances from reaching them, said the witnesses.

Israeli operation in Gaza encountered the resistance from the Palestinian militant groups, including Hamas, the Popular Resistance Committees (PRC) and a Fatah military wing.

Hamas, which seized Gaza after defeating rival Fatah in June, said in a statement that its members fired a rocket propelled grenade on an Israeli tank "and hit it directly."

The PRC said in a separate statement that its sniper targeted an Israeli soldier "and the soldier was seen falling from the tank on his face."

In a third statement, Fatah's al-Aqsa Martyrs Brigades said two of its members were injured during their armed clashes with an Israeli special force.