Britain, along with other European countries and the United States, is using Cyprus - which lies 16km away - as the hub of their operations for full-scale evacuations as the fighting intensifies.
The RAF base of Akrotiri is helping to co-ordinate plans among 15 countries trying to get their nationals out.
More than 2,400 Americans are being evacuated by air and sea on Wednesday, the first of up to 8,000 to be taken from Lebanon.
Canada said it would start evacuating its citizens by sea on Wednesday.
A Brazilian air force plane collected about 100 Brazilians who had reached Turkey from Beirut.
Six British ships, including two aircraft carriers, stood by to rescue British nationals.
The destroyer HMS Gloucester arrived in Limassol in Cyprus on Wednesday with 180 people from Beirut, and British prime minister Tony Blair said about 5,000 would be moved by the end of the week.
The evacuees on board the HMS Gloucester, which arrived in the southern port of Limassol were mainly "priority medical cases", many of them women and children.
"Britain is moving to a phased evacuation of British nationals," a foreign office spokeswoman said. "We believe there are some 12,000 British nationals in Lebanon."
France was hoping to move another 850 of its 10,000 citizens in Lebanon by ship to Cyprus through Israel's naval blockade, after taking out 800 on Tuesday, an embassy source said.Meanwhile, the Philippines said its efforts to find safe passage for about 30,000 Filipinos living in Lebanon were being hampered by a lack of funds.
Sweden was collecting 1,500 people early on Wednesday, while a Spanish airforce Boeing 707 flew 113 people out of Damascus, and more than 152 were being transported from Amman.
Russia sent emergencies ministry aircraft to pick up its evacuees, and Poland and Bulgaria hired buses to ferry their nationals and Czechs and Slovaks to Damascus.
Nine military ships, including a helicopter carrier, and thousands of Marines and sailors were involved in the US operation, US officials said.
A US chartered ship was scheduled to bring up to 900 people -mostly Americans and its largest group yet to leave Lebanon - under military escort to Cyprus on Wednesday. The US has an estimated 25,000 citizens in the country.
Thousands of Lebanese, as well as foreigners, have braved the road to Syria to flee from the Israeli bombardment that has killed 262 people in eight days, all but 27 of them civilians.
About 200 Belgians waited to get on buses from city centre of Beirut to the Syrian border.
Australia, the Philippines and New Zealand were all trying to locate buses and ships capable of carrying more than 30,000 people.
Nearly 5,000 Australian citizens are believed to be stranded in Lebanon and 25,000 dual Australian-Lebanese citizens living there.
Alexander Downer, the Australian foreign minister said: "We have chartered a Turkish ship to carry hundreds of Australians to Cyprus on Wednesday, but a gridlocked port in Beirut caused further delays."
Lyndall Sachs, Australia's ambassador to London expressed "grave concerns" for about 400 Australian families trapped in southern Lebanon.
"We've been in touch with a few of them, and they are facing shortages of food and water," she said, before calling for an Israeli cease-fire to secure safe evacuations.
"The problem is, we don't have ships where our nationals can board, unlike the US and French," said Gilbert Asuque, a spokesman from the department of foreign affairs.
Helen Tunnah, a spokeswoman for New Zealand's foreign affairs department, said the government was planning to move up to 90 New Zealanders to Cyprus, but was unsure when the evacuations would start. New Zealand has no diplomatic post in Lebanon.
A Russian family reunites after
fleeing from Lebanon
Lebanon's tourist season was approaching its height when the conflict erupted, stranding thousands of surprised foreigners.
Australian property developer Victor Kheir, 29 years old said: "It's my first time in Lebanon and probably my last.
"I came here to visit relatives, but an hour after I landed they bombed the airport."
Russians fleeing from south Lebanon described a distressing journey along deserted and bombed roads to Beirut.
"We went on bombed roads. The most frightening was not the shooting but the total silence. There was no one, not even a dog on the roads," one Russian woman from south Lebanon told state television.
A Lebanese family from south Lebanon mingled with the Belgians, hoping to be taken to safety with them. "We came from Baflay, where a whole family was massacred and two Kuwaitis were killed," said Zain Fatima, clutching her children.
"It's very bad, very sad, I can't believe what's happening," said a tearful Lubna Jaber, 28, an Australian who had come to visit relatives in Lebanon. She was waiting in downtown Beirut with about 350 compatriots to board buses and then a ferry to Turkey.
he United Nations has also begun to clear non-essential staff and family members out of the country.