More Israeli tanks and soldiers surged into southern Lebanon on Saturday, reaching the Litani River and engaging in some of the heaviest ground combat of the monthlong war just hours after the U.N. Security Council adopted a cease-fire plan.

The leader of the Islamic militant group Hezbollah grudgingly joined Lebanon’s government in accepting the U.N. resolution but vowed to keep fighting until Israeli troops leave and hand over territory to a muscular U.N. peacekeeping force intended to separate the antagonists.

Israel also signaled its intention to approve the plan, at a Cabinet meeting Sunday, and a senior official predicted fighting would stop Monday morning, but there was no slowing in the bloodshed.

Israel was determined to batter Hezbollah until the end, while the guerrillas seemed to be fighting as fiercely as ever after a month of intense Israeli air, artillery and ground assaults.

Israel said seven of its soldiers were killed and more than 70 wounded — Israel radio reported 100 wounded — in an expanded offensive that tripled Israeli troop strength in southern Lebanon to 30,000. Israel confirmed guerrillas shot down a helicopter, and Hezbollah claimed to destroy 21 tanks.

Israel said it killed more than 40 Hezbollah fighters. Hezbollah issued a statement saying three of its fighters had been killed but gave no date.

Nineteen Lebanese civilians died from Israeli airstrikes, while Hezollah rockets wounded eight people in northern Israel. The 32-day struggle has claimed nearly 900 lives, including at least 763 in Lebanon and 130 in Israel.

The big expansion of Israel troop strength prompted Hezbollah’s leader, Sheik Hassan Nasrallah, to declare the fight far from finished and likely to get worse.

“We must not make a mistake, not in the resistance, the government or the people, and believe that the war has ended. The war has not ended,” he said.

“Today nothing has changed and it appears tomorrow nothing will change,” Nasrallah added in his trademark measured tones.

Speaking a few hours before Lebanon’s Cabinet voted unanimously to accept the U.N. plan, Nasrallah said Hezbollah would abide by the cease-fire resolution but continue fighting as long as Israeli troops remained in Lebanon, calling it “our natural right.”

Lebanese Prime Minister Fuad Saniora said his Cabinet endorsed the cease-fire plan despite having reservations. “We will deal with the requirements of the resolution with realism in a way that serves the national interest,” he said.

The Cabinet harshly condemned Israel’s military push Saturday, saying it presented a “flagrant challenge” to the international community after the U.N. resolution was issued.

A senior Israeli official said the cease-fire was expected to go into effect at 7 a.m. Monday — midnight Sunday EDT.

The official, who spoke on condition of anonymity because he was not authorized to discuss sensitive issues publicly, said Israel wanted to seize control of the south so more Hezbollah fighters do not enter the zone before it is handed over to the Lebanese army and U.N. troops.

Defense Minister Amir Peretz said Israeli troops would remain until the international force arrived, and would defend themselves if attacked.

“If anyone dares to use force against Israeli defense forces, we will see this as a violation of the cease-fire agreement,” he said on Israel television.

Israel’s army chief, Lt. Gen. Dan Halutz, said ground forces had tripled in size in a bid to chase Hezbollah fighters and rocket crews north of the Litani, 18 miles north of the border. He did not give a specific figure, but a threefold increase would mean Israel had 30,000 soldiers inside Lebanon.

Lebanese security officials said Israel troops reached the Litani by helicopter at a point about six miles west of the northern tip of the Israeli panhandle that juts northward alongside southeastern Lebanon. The officials said the troops were near the village of Aalmane, which sits on high ground on the south side of the river.

The officials, who spoke on condition of anonymity because they were not authorized to speak to reporters, said the commandos cleared the area ahead of the arrival of a column of Israeli armored vehicles.

The Israelis used more than 50 helicopters to ferry hundreds of commandos into Hezbollah territory in the largest such operation in the Middle East since the October 1973 war.

President Bush had an eight-minute phone call Saturday with Saniora to discuss the U.N. resolution and efforts to end hostilities. The White House issued a statement declaring the administration was determined to vanquish the hold of Hezbollah — and that of its Syrian and Iranian benefactors — on the south.

“These steps are designed to stop Hezbollah from acting as a state within a state, and put an end to Iran and Syria’s efforts to hold the Lebanese people hostage to their own extremist agenda,” Bush said. “This in turn will help to restore the sovereignty of Lebanon’s democratic government and help ensure security for the people of Lebanon and Israel.”

Saniora, an anti-Syria politician whose government was extremely weak when the fighting began, appears to have emerged from the crisis considerably strengthened. He refused to give in to initial cease-fire proposals from the United States and France that would have left Israeli troops in place until an international force was installed.

He also prevailed in his insistence that policing of the cease-fire be done by Lebanese soldiers supported by a U.N. force rather than by an ad hoc assembly of international troops, possibly from NATO.

The cease-fire, unanimously adopted by the U.N. Security Council on Friday night, calls for a contingent of as many as 30,000 soldiers — half U.N., half Lebanese — to enforce the truce.

French President Jacques Chirac said his nation was ready to contribute troops. Italy and the predominantly Muslim nations of Turkey and Malaysia also have offered soldiers.

Israeli police said 64 rockets fell on northern Israel, wounding eight people. That compared with an average 200 missiles daily for the last two weeks.

At least 19 Lebanese civilians were killed in Israeli air raids Saturday. In the deadliest strike, Israeli missiles killed at least 15 civilians in the southern village of Rachaf, Lebanese security officials said.

Israeli warplanes also knocked out a highway in northern Lebanon leading to the Arida border crossing with Syria, the last official border post open for aid convoys and civilians fleeing the country. The only routes left were rugged footpaths and back roads through deserts or over mountains.

Aid convoys were stuck in ports or at warehouses because Israel refused to guarantee their safety on the roads. Thousands of people trapped in southern villages were believed to have run out of food and medicine and were drinking unsafe water.