Updated

Hundreds of U.S. citizens could leave Lebanon as early as Tuesday aboard a chartered Greek cruise ship, as evacuations of Americans and other foreigners continued in the face of the still raging Israeli-Hezbollah war.

The evacuation plan also would send more military helicopters to fly other American evacuees directly to the nearby Mediterranean island country of Cyprus, a Pentagon official said.

The U.S. government chartered the Orient Queen, a Greek registered cruise ship that can hold 750 passengers, to accommodate more of those wanting to leave, according to Pentagon spokesman Bryan Whitman. The vessel would be ready to ferry people to Cyprus on Tuesday, he said.

The ship would be accompanied if necessary by a military escort, a destroyer vessel called the U.S.S. Gonzalez, according to Whitman.

Americans were flown on U.S. choppers from the Lebanese capital of Beirut to Cyprus, 125 miles away, on Sunday and Monday.

Three CH-53 choppers, each of which can transport about 30 passengers, were already airlifting Americans from the embassy to Cyprus, with more on the way Tuesday as the pace of air and sea evacuations was expected to increase.

Some, however, were still stuck in Lebanon.

"It's pretty chaotic," Patricia Stefanovic Rabil, the mother of a small child, told FOX News in a phone interview. "Not having information ... is very frustrating."

Click here for FOXNews.com's Mideast Center.

Whitman said that several hundred people who want to evacuate have contacted the U.S. Embassy in Beirut.

However, Americans who wish to leave Lebanon should not go to the embassy, the State Department warned.

Because of the dangerous situation at hand, they should pack only one suitcase (of a weight not to exceed 30 pounds, or 15 kilos), prepare important travel documents — including U.S. passports, birth certificates, marriage papers and so on — and stay put to await further instructions.

Those instructions will be disseminated via the media, the Embassy warden system and the U.S. Embassy Web site, the State Department advised. Pets will not be allowed to travel.

Whitman said plans were being made in the possible event of a Hezbollah attack on the evacuation operation.

"We'll take all appropriate measures and precautions," he said, declining to offer specifics.

Meanwhile, about 2,000 U.S. Marines have ended an annual exercise in Jordan and they, along with the U.S.S. Iwo Jima in the Red Sea, were available if needed, according to the Pentagon. It would take several days for Iwo Jima to get to the eastern Mediterranean to help with transporting people out of Lebanon, however.

CountryWatch: Lebanon

Two U.S. Marine Corps helicopters evacuated 21 Americans on Sunday, flying from the U.S. Embassy's fortified grounds on a hilltop in a Beirut suburb. U.S. security teams also landed to begin planning the evacuation of others.

More than 100 Marines were in Cyprus to prepare for the operation.

European governments also stepped up efforts to move their nationals to safety.

Hundreds of foreigners, including tourists and dual nationals, have been moved through Cyprus since Israel began its attacks on Lebanon last Wednesday in response to attacks from Hezbollah militants.

CountryWatch: Israel

An Italian warship carrying nearly 400 evacuees was expected in the Cyprus port of Larnaca on Monday afternoon. The evacuees were headed to Beirut on a convoy of 17 buses, Italian authorities said.

The Cyprus government made preparations to help with the evacuation of thousands more expected to be brought out by the United States and European countries.

"At this stage we don't have an exact number of people. ... We'll surely have four or five ships this week alone," Foreign Ministry official Omiros Mavromatis said after a government meeting with civil defense, health and military officials.

Greece reportedly is sending a navy frigate to a Lebanese port to pick up 100 people and has three additional warships on standby.

France, which has more than 20,000 citizens in Lebanon, chartered a Greek ferry, the Lerapetra, to pick up as many as 1,200 French and other European citizens in Lebanon.

Military planes brought 350 people to the island on Sunday, and 40 Britons and 21 Americans were flown by helicopter to Britain's Akrotiri military base on Cyprus.

About 850 Swedes from among about 5,000 in Lebanon have been evacuated, largely to the city of Aleppo in northern Syria, where most of them remain. Sweden has chartered three ships to bring Swedes from Beirut to Cyprus, but is awaiting security guarantees from the warring parties.

A British aircraft carrier and another warship — both already in the Mediterranean — set off Sunday on a three-day trip to the Middle East in preparation for the possible evacuation of Britons.

A British Foreign Office spokesman said the first wave of Britons — children, elderly and ill people, left Sunday aboard the helicopter that transported European Union foreign policy chief Javier Solana, who met with Lebanese Prime Minister Fuad Saniora on Sunday in Beirut.

Denmark began evacuating some 2,300 people by bus to Damascus, Syria. So far, some 700 have returned home, the Danish government said.

Ukraine said its embassy in Lebanon rented 14 buses to begin the evacuation of 520 Ukrainians from Beirut. They were to be taken to the airport in the Syrian city of Latakia, where three flights were scheduled to pick them up and take them home.

Russia's Foreign Ministry said there were more than 1,400 Russian citizens in Lebanon, and RIA-Novosti and ITAR-Tass news agencies quoted Russia's charge d'affaires there as saying more than 1,000 were ready to leave.

FOX News' Catherine Donaldson-Evans, Nick Simeone and The Associated Press contributed to this report.