On the Israel-Lebanon border ? Israel massed tanks and troops on the border Friday hours after calling up reserves, as the army announced plans for a ground operation to destroy Hezbollah’s tunnels, hideouts and weapons stashes.

With Hezbollah’s rocket attacks and Israeli bombings undiminished, Secretary of State Condoleezza Rice said she would visit the Middle East beginning Sunday – her first trip to the region since the crisis erupted 10 days ago. But she ruled out a quick cease-fire between Israel and the Shiite guerrillas as a “false promise.”

Israel, which pulled its troops out of Lebanon just six years ago after a lengthy and costly occupation that caused painful divisions within the Jewish state, was poised to carry out its third large-scale ground operation in Lebanon since 1978. This time, however, the Israelis signaled they did not want to stay long.

Israel hopes the operation will end in the neutralization of Hezbollah. But the operation carries great risks for the country and the region. If Lebanon’s weak central government is undermined, it could immerse the country again into disorder and ignite fresh passions in many Arab countries against Israel and the United States.

On Friday, the Israeli army confirmed that small units have been operating in Lebanon for days. An official from the U.N. monitoring force in south Lebanon said 300 to 500 Israeli troops were believed to be in the western sector of the border, backed by as many as 30 tanks – a likely precursor to a larger ground force that Israel could use to sweep Hezbollah out of the area.

Members of Lebanese families fleeing from Israeli forces' bombardment of their southern village of Bazouriyeh, Lebanon, arrive atop a truck in the coastal town of Tyre.

Israel’s goal is not to create a buffer zone as it did during its occupation of southern Lebanon from 1982 to 2000, said a senior military official, speaking on condition of anonymity because of the topic’s military sensitivity.

Rather, Israel wants to weaken Hezbollah with a limited ground operation to make it easier for the Lebanese army to move into areas previously controlled by the guerrillas, possibly with the aid of a beefed-up international peacekeeping force, the official said.

On Friday, Israel knocked out a key bridge on the road to Syria and pummeled Hezbollah positions in the south as long lines of tanks and armored personnel carriers lined up at the border – in some places close enough to see Lebanese homes on the other side.

Ships lined up at Beirut’s port as a massive evacuation of Americans and other foreigners picked up speed. U.S. officials said about 5,000 Americans were leaving Friday, bringing the total evacuated to more than 8,000.