Hundreds of Americans and Russians were reported stranded in the heart of Lebanon's war zone Tuesday when a ship evacuating foreigners had to pull out of a southern port without them.

The Cypriot ship Princesa Marissa picked up about 300 foreigners stuck in the southern port city of Tyre — a joint effort by the U.S., Switzerland, Norway and others, said Erik Rattat, a German official involved in the evacuation.

Rattat said 300 Americans trapped southeast of Tyre had called the U.S. Embassy for help. He said the embassy called him and asked that the Cypriot ship wait as long as possible for the Americans to get on board. But the boat had a deadline to leave by 5 p.m., he said.

U.S. officials confirmed they had been trying to get Americans onto the ship, but were unsure if any had made it on time. The last scheduled evacuations of Americans from Lebanon were planned for Wednesday, U.S. officials said.

A Canadian ship was due in Tyre on Wednesday to evacuate more people, officials said.

Boatloads of evacuees have been leaving from Beirut for nearly a week, but Israeli airstrikes have damaged roads leading to the capital, and few people in the south have risked the trip.

More than 12,000 Americans have fled Lebanon since hostilities started two weeks ago, and officials said the effort was winding down.

Russian Foreign Minister Sergey Lavrov said more than 100 Russians and citizens of other ex-Soviet republics also might be caught in Lebanon's south, the stronghold of the Hezbollah militant group targeted by Israel's offensive. Russia and Israel were negotiating a safe corridor for their passage to the Syrian border, he said.

Nearly 2,000 citizens from Russia and other ex-Soviet republics have been evacuated, and scores more were to be bused from Beirut to Syria this week, Lavrov said.

CountryWatch: Israel | Lebanon | Syria | Iran

The Princess Marissa boat arrived at Larnaca, Cyprus, after midnight Tuesday carrying some 230 mostly European nationals. Ambulances stood by for several injured evacuees.

Some 500 Americans left Monday morning on the USS Nashville, a troop transport vessel that last week took multiple loads of more than 1,000 people. It had been scheduled to leave Sunday, but did not fill up, and officials held it in port overnight.

The cruise ship Orient Queen left Beirut on Monday night with several hundred more American evacuees, U.S. officials said.

U.S. Embassy officials said they were meeting Monday night to discuss whether to reduce the fleet of seven naval ships involved in the effort.

Pentagon spokesman Bryan Whitman said the U.S. military would shift to a humanitarian mission, carrying tons of medical equipment and other supplies from Cyprus to Beirut.

The last large group of Britons requesting evacuation sailed out of Beirut's harbor Sunday. The British have pulled out a total of about 4,500 people.

Canadian officials said about 1,200 of their nationals left on two ships Monday, bringing the total number of Canadians evacuated to nearly 8,000. Officials said they had stopped phoning Canadians to notify them of evacuations and urged them to report to boarding areas without waiting for a call.