By Sarah Rainsford
BBC News, Beirut
America is stepping up its evacuation operation from Lebanon.
Thousands of Americans have left, but thousands remain in Lebanon
At a police base in Beirut, US Marines are registering thousands of US citizens anxious to flee the violence.
They have moved over 4,000 evacuees in the past 36 hours; teams here are aiming to double that number at least over the weekend.
The system these days is first-come, first-served - so many people queue from 0500. Marines are on hand offering water and words of comfort, but in the baking Beirut sunshine it is a long, hot wait.
"The past days were scary; there was a lot of bombing," Nada says as she drags a large suitcase across the tarmac.
"I'm glad I made it here safely. But I'm leaving my parents behind," she adds, choking back tears. "I hope they will be safe, and I will see them again."
World 'just watches'
"I hope the world realises the amount of damage and destruction being done to this great country," says Nasser, a Lebanese-American who was visiting Beirut on holiday.
"You would imagine that after 350 innocent people were killed the world would say something. The country - and our hopes and dreams - have been completely destroyed by this."
Evacuations are by ship as Israeli strikes closed Beirut airport
Most of these evacuees are fleeing the Beirut area. But thousands of US citizens are still trapped in southern Lebanon, where the bombing has been more intense.
Ibrahim and his family had been on holiday with family in Tyre. This week the three houses nearest theirs were destroyed by bombs. Seven people were killed.
"How could our government allow this to happen? Where we supply all the armoury to Israel and then allow this to happen to us. Can't they tell Israel to stop bombing for a day and let us go?" Ibrahim fumes as he waits in line to leave the country.
His brother had to risk the hazardous drive to Beirut to make sure the family reached a ship out.
"There's no such thing as a secure place. They bomb civilians now. They don't care. And the whole world is watching - it's amazing!"
Parting is especially hard for those leaving family and friends behind
This holiday experience has matured 11-year old Azim far beyond his years.
"The bombings were really close. We had to go underground. We hid there while the bombs were surrounding us," he says.
"It was really frightening. I heard children screaming. My mum was just praying to God that we would be safe."
The US embassy says more than 300 US passport holders were brought to Beirut from the south by bus on Wednesday, and transferred by sea.
"When we see an opportunity to stage a bus pick-up in the south we make it known through our networks there, but no immediate site has been selected for soon," explains Christopher Murray of the US embassy.
"The south is our biggest challenge, but the situation there is very dangerous. Our vehicles may be threatened. We are very concerned."
Once through the registration process on the base, families who have made it to Beirut wind their way down to the beach for evacuation to one of five Navy ships moored off the coast.
US Marines carry small children across the sand and stones; Lebanese police carry an elderly woman in a wheelchair. Passengers struggle with their luggage.
"I feel as safe as if I was in my mother's arms right now," Brig Gen Carl Jensen says, when asked how risky the sea evacuation actually is.
"Believe me there are layers upon layers of security and defence rings. We have cruisers protecting the ships going in and out. We know how precious the cargo is."
On board the USS Trenton, khaki-coloured camp-beds fill every open space. Evacuees are sprawled everywhere - on the deck, in corridors, even in the crew's quarters.
There is free hot food for everyone. Films are playing in the mess, and passengers can contact relatives at home via phone or Internet.
For more than 1,800 evacuees on board, there is also a huge, collective sense of relief.
"I hope we will be able to go back to Lebanon in a month. If not I don't know if we will ever return," Aida says - squatting with her children on a mattress in the ship's mess.
"I grew up here during the war and I don't want my kids to do the same. That's why I left. There is no way they should go through that."