Hundreds of Hamas security forces trained for a possible Israeli incursion into the Gaza Strip, firing automatic rifles and shoulder-held grenade launchers in their first extensive exercise since they overran the coastal territory in June.

Hamas has said it is preparing for the possibility that Israel will launch a large military operation in the Gaza Strip. Israeli Prime Minister Ehud Olmert's government is under public pressure to respond to recent Palestinian rocket attacks on southern Israel.

On Saturday, Israeli Foreign Minister Tzipi Livni said the government was considering several kinds of retaliation, not just military, in an apparent reference to recent calls for Israel to cut off the supply of electricity, fuel and water to the Gaza Strip in an effort to get the Hamas rulers there to stop the rocket fire.

"I think there are a series of actions other than military actions" that Israel can take, Livni told Army Radio. She did not elaborate but said the actions would not necessarily constitute "collective punishment.'

Israelis should not expect that the government will be able to totally stop the rocket fire, Livni said.

Olmert's Cabinet was slated Sunday to further debate retaliation in an effort to stop the rockets.

The Cabinet would not vote, as had been planned on Sunday, on the proposed release of Palestinian prisoners that was meant to be a gesture to the moderate Palestinian President Mahmoud Abbas, Olmert's office said.

Olmert had offered the release, reportedly of about 100 prisoners, during a meeting between the leaders last week as part of Israeli efforts to bolster the Western-backed Abbas of the moderate Fatah movement in facing its rival, Hamas, after the Islamic group took over the Gaza Strip in June.

In the Hamas drill Friday in the northern Gazan town of Beit Lahiya, Hamas forces in black ski masks and camouflage ran between fig trees and corn stalks, shooting toward a purported target. They took cover behind mounds of sand, hid in half-destroyed houses and in trenches.

At one point they fired at an empty house, causing a large explosion. They then kneeled to the ground, shouting "Allah Akbar," or "God is great."

The military exercise was the first in which Hamas invited the media since the Islamic group took over the Gaza Strip in five days of bloody fighting. Hamas now rules the Gaza Strip, while Fatah controls the West Bank after Abbas dissolved the Hamas-lead government, naming a moderate Cabinet in its place.

Hamas forces are better equipped than at the time of previous Israeli incursions since they confiscated weapons from Fatah during the fighting in June, senior Hamas official Nizar Rayyan said.

"Your brothers, the sons of Hamas ... have the weapons that they claimed as booty from the war of cleansing (against Fatah) and will now fight the state of Israel with them," Rayyan said.

During any such Israeli operation, Hamas would kidnap Israeli soldiers, Rayyan said.

On Saturday, a small group affiliated with Hamas, the Popular Resistance Committees, held a military drill in an open field in Gaza City. About 60 militants laid explosives in the ground and fired at imaginary targets.

"We will surprise the enemy with our ferocious fighting," said Abu Youssef, the group's spokesman.

In violence Saturday, Israeli tanks crossed more than 250 meters (yards) into the northern Gaza Strip in an operation to rout out rocket launchers, the army said. In an exchange of fire in the town of Beit Hanoun, one Palestinian, 17, was seriously injured, Palestinian health officials said. Local residents said the youth was not known as a militant.

The army said troops responded with fire after they were shot at, including with RPGs. Islamic Jihad said it fired two RPGs at the troops. The soldiers detained nine Palestinians for questioning, the army said.

Israel frequently carries out incursions in the Gaza Strip against militants who launch rockets. The projectiles are fired almost daily, wreak panic in southern Israel and occasionally cause casualties.