KOH LIPE, Thailand (REUTERS) - Malaysian vessels on Saturday intercepted a boat crammed with migrants after the Thai navy towed it away from Thailand, the latest of a number of vessels pushed back to sea by governments who have ignored a UN call for an immediate rescue.

Thousands of people are adrift in the Andaman Sea after smugglers abandoned their vessels following a Thai crackdown on human trafficking. Many of the migrants are thirsty and sick.

Migrants aboard the vessel were visibly distressed on the packed deck under a blazing sun, a Reuters witness said. Women were crying and some waved their arms and shouted, he said.

The boat has been towed back out to sea by the Thai navy twice after drifting for days. On both occasions, the navy fixed its engine and supplied it with food, water and fuel before towing it out of Thai waters.

The migrants told the Thai navy on Saturday that they wanted to go to Malaysia, the officer aboard a patrol boat told Reuters. "We fixed their engine and showed them where Malaysia is,"the officer said.

After the Thais released it, the boat entered neighbouring Malaysian waters where it was intercepted, he said. He declined to give his name.

It was unclear what the Malaysian authorities would do with the migrants. But Malaysia's government said this week it would push boats back to sea as it did not want to receive large numbers of illegal migrants.

The International Organization for Migration has criticised the region's governments for playing "maritime ping-pong" with the migrants and endangering their lives.

The United Nations this week urged governments to fulfil an obligation to rescue those at sea and "keep their borders and ports open ... to help the vulnerable people who are in need".

But there was no sign of a coordinated rescue operation, the UN refugee agency UNHCR said on Saturday. "We're not seeing any such moves from any governments in the region even though we're calling on the international community to take action because people are dying," Jeffrey Savage, who works with the UNHCR in Indonesia, told Reuters on Saturday.

While many remain at sea, thousands have made it to land. Nearly 800 migrants came ashore in Aceh in Indonesia on Friday, taking the number that have made land in Indonesia and the northwest of Malaysia to more than 2,500 over the past week.

Thailand found 106 more migrants on Friday on an island in the southern province of Phang Nga, provincial governor Prayoon Rattanasenee told Reuters. It was unclear how they got there, he said.

"Most of them are men but there are also women and children," Prayoon said. "We are trying to determine whether they were victims of human trafficking."

The Thai clamp-down has made the preferred trafficking route through Thailand too risky for criminals preying on Rohingya Muslims fleeing persecution in Myanmar and Bangladeshis seeking to escape poverty.

An estimated 25,000 Bangladeshis and Rohingya boarded smugglers' boats in the first three months of this year, twice as many in the same period of 2014, the UNHCR has said.

The United Nations said the deadly pattern of migration by sea across the Bay of Bengal would continue unless Myanmar ended discrimination. Most of Myanmar's 1.1 million Rohingya Muslims are stateless and live in apartheid-like conditions in Rakhine state in the west of the predominantly Buddhist country.

Almost 140,000 were displaced in clashes with ethnic Rakhine Buddhists in 2012.

Myanmar uses the term "Bengalis" for the Rohingya, a name most Rohingya reject because it implies they are immigrants from Bangladesh despite having lived in Myanmar for generations.

Thailand is hosting talks on May 29 for 15 countries to discuss migration in the region. Myanmar had not received an invitation to the talks and would not attend if the word Rohingya was used, Zaw Htay, a senior official from the president's office, said on Saturday.

"We haven't received any formal invitation from Thailand officially yet," he said in an emailed response to questions from Reuters. "And another thing, if they use the term 'Rohingya' we won't take part in it since we don't recognise this term. The Myanmar government has been protesting against the use of it all along."