President Bush is blaming Iran and Syria for Hezbollah’s killing of eight Israeli soldiers and kidnapping of two more, prompting the shelling of southern Lebanon, the bombing of strategic targets just south of Beirut, and preparations for an imminent full-scale invasion of Lebanon by Israeli forces.

The Israeli army’s chief of staff, Lieutenant General Dan Halutz, yesterday said on television that the military operations being planned would “turn back the clock in Lebanon by 20 years” if the kidnapped soldiers were not returned.

Meanwhile, Prime Minister Olmert yesterday declared the cross-border killings and kidnappings were “an act of war” by Hezbollah, an organization the Israelis have long said was funded and armed by Syria and Iran. The attacks in the north started yesterday when Israel bombed bridges and other targets in southern Lebanon.

The kidnapping of an Israeli corporal, Gilad Shalit, from a Gaza border guard post by Hamas terrorists and now the kidnapping of two more Israeli soldiers, this time by Hezbollah terrorists, is seen as a severe test of the Israeli premier, a former mayor of Jerusalem who has had little military experience and inherited his post from Ariel Sharon, an Israeli military hero.

First indications suggested that Mr. Olmert was equal to the task. He immediately called up 6,000 reservists yesterday and put into effect plans for an extended incursion into southern Lebanon, which has long hosted Hezbollah terrorists. The intention appeared to be to dismantle the extensive network of terrorist bases and persuade the Beirut government to meet international calls to disarm the group once and for all.

Israeli forces went on the attack, targeting bridges, communication towers, military bunkers, and other facilities. At least two Lebanese civilians were reported to have been killed in the attacks.

“It is absolutely clear to the international community that Israel will respond and that it will respond in an unequivocal fashion that will cause those who started this act of war to bear a very painful and far-reaching responsibility for their actions,” Mr. Olmert said.

But the return to Lebanon will inevitably raise fears of Israel repeating the mistakes it made during its 22-year occupation of southern Lebanon, which ended six years ago after more than 1,000 Israeli soldiers had died.

Those blamed by President Bush for the escalation of terrorist violence in the Middle East were unrepentant yesterday. Iran’s chief nuclear negotiator, Ali Larijani, was in Damascus yesterday and at a press conference said, “When the Zionist entity attacks and slaughters the Palestinian people . . . resistance is necessary,” according to the Associated Press.

Syria’s vice president, Farouk al-Sharaa, who appeared with Mr. Larijani, said Syria played no role in the attack and that the decision “was up to the resistance.” Spokesmen for Hezbollah yesterday said the soldiers would not be returned until Israel released Palestinian Arab prisoners.

The kidnapping yesterday morning was only hours before the five permanent members of the U.N. Security Council plus Germany voted in Paris to refer Iran’s transgressions under the nuclear nonproliferation treaty to the U.N. Security Council, effectively withdrawing for now the package of incentives offered to Iran in the last two months as a way to entice Tehran to end its enrichment of uranium.

The timing of Iran’s latest brinksmanship and the Hezbollah attack appear to be linked. Rhetoric in recent weeks from the regime in Tehran and its ally in Damascus has stepped up against both Israel and the west. Meanwhile, Israeli intelligence in the last month has been warning of a new offensive from Hezbollah on the northern border, according to one Israeli official.

The connection with Syria, a country America and Israel say funnels arms to Hezbollah in southern Lebanon and has attempted to ship weapons to the Palestinian Arab terrorist organization Hamas, also does not appear to be coincidental. In the last year, Damascus has turned to Iran for protection and funding after Saudi Arabia, Egypt, and most European countries turned on Syrian President Assad in the wake of the assassination of Lebanon’s former prime minister, Rafik Hariri.

Egypt’s president, Hosni Mubarak, yesterday called Mr. Assad after the incursion by Israeli forces into Lebanon. According to an interview yesterday in the state-funded al-Ahram newspaper, the Egyptian leader all but named Syria as the spoiler in his efforts to negotiate the return of the Israeli soldier kidnapped two weeks ago by Hamas.

Hamas was subject to “counter-pressures by other parties, which I don’t want to name but which cut the road in front of the Egyptian mediation and led to the failure of the deal after it was about to be concluded,” Mr. Mubarak said.

An expert on the Levant region at the Foundation for the Defense of Democracies, Tony Badran, yesterday said the Syrians were hoping to make themselves indispensable for America and outside powers, as a key to the region’s stability.

“Bashar Assad is trying to make himself an indispensable player. He has [Hamas military terrorist leader] Khaled Meshaal, and he hopes this gives you recognition as a party without whom nothing else works,” he said. “This is a way for him to use blackmail and violence in order to break out of his international isolation. But so far no one has bought it.”

On Tuesday, Syria’s official news agency reported that the country’s deputy foreign minister expressed an interest in joining a peace negotiation with Israel in meetings at Russia’s foreign ministry. Israeli jets two weeks ago buzzed the summer palace of President Assad, sending the clear message that, if so ordered, the jets could drop their payloads.

Israel enjoyed a minor military success yesterday. A military spokesman said that a quarter ton bomb Israeli jets dropped on a Gaza home injured the head of Hamas’s military wing, Mohammed Deif. The bomb also killed a couple and seven of their children. The Associated Press reported that Hamas took over the intensive care unit in the hospital where the victims of the blast were rushed. Fox News Channel reported that Israel had also bombed the Hamas-controlled Palestinian foreign ministry building in Gaza.

A statement from the White House blamed Iran and Syria for the violence, while Secretary of State Rice said, “All sides must act with restraint to resolve this incident peacefully and to protect innocent life and civilian infrastructure.”

In Rome, the U.N. secretary-general, Kofi Annan, said, “The leaders in the region and around the world should use their influence to press the parties to show restraint and resolve this situation.”