* Libya migrants say 500-600 in boat sunk off Tripoli
* Tell agency Libyan troops forced them to embark
GENEVA, May 9 (Reuters) - Traumatised migrants have told the International Organization for Migration (IOM) they saw a boat carrying hundreds of people founder off the Libyan coast last week, the agency said on Monday.
The migrants who reached Italy’s Lampedusa island, a collection point, also said Libyan soldiers drove them onto another vessel in what IOM officials said was the first known forced evacuation from Libya in the current conflict.
The sinking boat was seen between Thursday and Friday last week just off Tripoli, the Libyan capital controlled by forces loyal to Mummar Gaddafi. It had been carrying 500 to 600 people, the IOM said, citing the migrants it had interviewed.
They saw bodies washed ashore in Libya and it was not clear how many survived. One Somali woman managed to swim to land and board another vessel, but she lost her four-month-old baby who had been with her, the agency said.
“She was in a state of shock when she arrived on Lampedusa,” Daria Storia of the IOM said. “She was clearly very disorientated and agitated when we spoke to her.”
There are increasing reports of boat tragedies in the Mediterranean as desperate migrants seek to flee the Libyan conflict.
Since unrest erupted across much of North Africa earlier this year, more than 10,000 migrants of various nationalities, have arrived on Lampedusa, situated between Sicily and Tunisia, and the neighbouring island of Linosa.
This weekend alone nearly 2,000 people arrived on five boats, according to IOM figures.
In a rescue operation alongside other humanitarian agencies, the Geneva-based IOM has evacuated 6,263 people from Misrata to Benghazi, effectively the rebel capital in the east of the country.
The IOM said that after the migrants saw one vessel sinking late last week, many had decided against trying to get to Italy, but they told the IMO Libyan soldiers and officials had forced them on to another boat by shooting into the air.
“People have been arriving in Lampedusa for about five weeks. This is the first time people have said they were forced,” said Jean-Philippe Chauzy of the IOM.
Many of the migrants from Libya had said they have not had to pay for their passage, others said they had paid a nominal fee and some said that soldiers and officials had stripped them of their savings and possessions, including mobile phones.
Tunisian migrants arriving on Lampedusa have been paying up to 1,200 euros ($1,676) to make the sea journey on smugglers’ boats from Tunisia.
Reporting by Barbara Lewis; editing by Robert Evans