A Palestinian rocket exploded in an Israeli army base early Tuesday, wounding more than 40 soldiers as they slept in their tents and drawing calls for a major military operation against militants launching rockets from the Gaza Strip.

The injury toll was the highest ever sustained in a single Palestinian rocket attack. Prime Minister Ehud Olmert was meeting Tuesday with top military and security officials, and discussions were expected to include possible responses to the attack, Israeli officials said.

The wounded soldiers were all recent recruits undergoing basic training at the army's Zikim base, just north of the Gaza-Israel border, and were asleep when the rocket hit an empty tent, the army said. Of the more than 40 soldiers in nearby tents who were wounded, 12 remained in serious condition, the army said.

A Hamas spokesman praised the rocket attack, calling it a "victory from God."

"We consider this a victory from God for the resistance," Hamas spokesman Fawzi Barhoum said on Hamas radio. "We consider the resistance as the legitimate right of the Palestinians to defend themselves and restore their rights."

Two small extremist groups, Islamic Jihad and the Popular Resistance Committees, claimed responsibility for the attack in a joint statement faxed to reporters.

The Israeli army said its ground forces struck back at the area militants used to launch the strike. A Gaza health official said four civilians, including children, were wounded.

Ambulances roared up to the base's gate after the rocket hit before 2 a.m., and army helicopters evacuated the seriously wounded. The emergency room at Barzilai Hospital in the nearby city of Ashkelon was swamped with incoming casualties, and medics emerged from the hospital carrying empty stretchers covered in blood.

The strike came at a time when Israeli politicians and defense officials have been calling for a more aggressive Israeli response to the near-daily rocket barrages out of Gaza. Attacks last week on the frequently targeted town of Sderot, including one near a crowded nursery school, led parents to pull their children out of school and brought demands for harsh retaliation.

"The question is not whether to create deterrence, but when," said Public Security Minister Avi Dichter, a member of Olmert's ruling Kadima party, told Israel Radio.

Cabinet minister Eli Yishai told Army Radio, "Long ago, several years ago, we should have responded strongly ... In the end we will have no choice but to act."

Four Palestinian civilians between ages 5 and 21, members of the same family, were wounded in the initial army response, according to Dr. Muawiya Hassanin of Gaza's Health Ministry. Two were treated briefly and released, and two girls — ages 7 and 17 — remained hospitalized, Hassanin said. The army would not immediately confirm any civilian injuries.

Fearing retaliation, Islamic Jihad ordered its militants to avoid using cell phones and public transportation so they could not be tracked and targeted by Israeli forces.

Islamic Jihad has been responsible for nearly all rocket fire out of Gaza in recent weeks. But Israel has said it holds Hamas responsible for the violence, since the militant movement controls Gaza and has done nothing to halt the attacks.

"It doesn't matter which terror group took responsibility. Gaza is totally controlled by Hamas, and it has the ability to stop this and decided not to," Israeli Foreign Minister Tzipi Livni said at a news conference. "I think we have tools to do this, tools that are not only military," said Livni, who has hinted that Israel should cut fuel or power supplies to Gaza in response to the attacks.

In Gaza City and in the southern Gaza town of Rafah, youths in Islamic Jihad scarves and T-shirts handed out sweets to motorists.

"This is a very strong operation. I salute the Al-Quds Brigades, and I say to them that such operations have restored the credibility and honor of this nation," said Ahmad el-Sheikh, a shopkeeper in Rafah, referring to Islamic Jihad's military wing.

Another rocket hit an Israeli kibbutz near Gaza later Tuesday morning. Hamas militants also announced they had launched a mortar barrage at Kerem Shalom, a border crossing where humanitarian aid crosses from Israel into Gaza. There were no casualties in either attack.

Crude homemade rockets land in southern Israel nearly every day. Although the rockets are inaccurate, they have killed 12 people in the past seven years, injured dozens and disrupted daily life in the area.

Israel's Security Cabinet last week rejected calls for a large-scale Gaza invasion but threatened to cut water, electricity and fuel supplies to the impoverished strip. Tuesday's attack could increase pressure on Olmert to order a major ground offensive in Gaza.

Israel pulled out of Gaza in 2005, ending 38 years of military rule, but militants continued launching rockets at Israeli towns. The Israeli army has mounted several large-scale military operations in Gaza over the past two years, with heavy casualties on both sides, but those moves had no long-term effect on the number of rockets hitting Israel.