THE ANDAMAN SEA (Reuters) - For several days, the fate of roughly 300 desperate Rohingya and Bangladeshi migrants has been subject to a repetitive dance in waters just out of sight of gleaming Thai beach resorts.

Their boat, which those on board said had been at sea for up to three months, was found drifting last Thursday off Koh Lipe island, near the Malaysian border, with parts of its engine missing. Thai sailors fixed the engine and handed the migrants food and water, before turning them back out to the Andaman Sea.

That was the beginning of what local Thai navy chief Veerapong Nakprasit calls "a cycle", with the overcrowded fishing vessel bouncing between the waters of two countries, both determined not to take the migrants in.

This rickety boat was just one of many at the centre of a regional crisis triggered by a growing flood of Bangladeshis and Rohingya Muslims from Myanmar. Migrants have long made their way from the Bay of Bengal's south-eastern corner to Thailand, but a crackdown on traffickers by the Thai government has disrupted the route. Several thousand were left at sea with nowhere to go, although more than 2,000 did make it to the shores of Malaysia and Indonesia.

Thailand's Foreign Ministry said in a statement that it had informed the people on the boat found off Koh Lipe that they could come ashore for humanitarian assistance, but "they informed the Thai side that they wished to travel onwards". After being towed out last Friday, it headed south-west, according to Thai navy radar tracking seen by Reuters.

It then took a jagged counterclockwise arc towards Malaysian waters, before its engine stopped and it drifted again in the sea.

Piecing together what happened to the migrants after that is difficult because of contradictory accounts from Thai officials and near-total silence from Malaysia.

Last Saturday, Reuters journalists in a speedboat spotted the boat tethered to the side of a Thai navy patrol vessel. The boat's engine was running, and it was being dragged south-west across the Malacca Strait towards Indonesia's Aceh province.

As the Reuters team pulled alongside the boat, hundreds of rake-thin migrants could be seen huddling on the deck. They were trying to shield themselves from the harsh sun with whatever was at hand, including torn-up boxes that had contained food handed to them by the Thai navy.

Men shouted from the boat, but could not be heard above the din of the engines. Women and children stared out and cried. As Thai sailors yelled "Go away! Go, go!" at the journalists, the boat was released, and it again arced under its own power back towards Malaysia, where two Malaysian vessels were seen intercepting it.

A Thai navy officer, who declined to be named, described tension and increasing desperation on the boat. He said it appeared to be under the control of two or three "agents", who insisted on going to Malaysia - despite objections from some passengers - and had hoarded food and water provided by the military. The boat's engine was found last Saturday with water in it, a possible sign that it had been sabotaged, according to the Thai officer.

Several hours later, another Reuters team spotted the migrants' vessel, again tethered to the Thai navy patrol boat. It was unclear if it had been pushed back by the Malaysians.

Lieutenant-Commander Veerapong said that, as of last Saturday night, it had been turned and was heading again in the direction of Indonesia.