Indonesian military has told Al Jazeera that they will send back any boat with Rohingya migrants entering its waters as a vessel carrying hundreds of migrants from Myanmar and Bangladesh was turned away towards Malaysia.

Fuad Basya, Indonesian military spokesperson, said they pulled back a boat "full of people in dire conditions, smelling bad, some were screaming", adding that they provided the migrants with water, food, medicine and fuel.

AFP news agency reported that the boat carrying an estimated 400 migrants was intercepted on the coast of northwestern Aceh region on Monday.

Rohingya migrants' desperate escape from Myanmar

Meanwhile, rights groups have urged regional governments to save thousands of migrants believed to be stranded at sea in Southeast Asia and at the risk of death.

An estimated 6,000 to 8,000 Bangladeshis and Rohingya Muslims from Myanmar remain trapped in crowded, wooden boats, officials and activists said on Tuesday.

Nearly 2,000 people have reached Malaysia and Indonesia in the past two days after Thailand announced a crackdown on smuggling routes. They were rescued from overcrowded boats after being stranded at sea.

Myanmar shirks responsibility

Even as a large number of migrants originated from Myanmar, its government said that they will not take responsibility for migrants who are not their own citizens.

"If it is true and proven that they are from Myanmar, we will take responsibility for them. But not the Bangladeshis," Zaw Htay, the director of Myanmar's president's office told Al Jazeera.

"Some of the Rohingya people may have come from Bangladesh. We can't be responsible for them. But we do not accept the name Rohingya. They are Bengali," Htay added referring to Myanmar's long-persecuted Rohingya Muslim community.

The Rohingya, who are Muslim, have for decades suffered from state-sanctioned discrimination in Buddhist-majority Myanmar, which considers them illegal settlers from Bangladesh even though their families have lived there for generations.

Those comments come a day after more than a 1,000 migrants, including children from both countries, were detained in Malaysia after they arrived in the popular Malaysian resort island of Langkawi.

The police chief in Langkawi told Al Jazeera's Karishma Vyas that 1,158 people were being held on the island. At least 672 are Bangladeshi, and around 486 of them are Rohingya Muslims from Myanmar.

At least 100 women and 60 children were among them. The migrants were in a very poor state, suffering from dehydration as well as hunger.

The police say they believe the captain as well as the other traffickers on the three boats had escaped in another vessel and left the migrants to their own devices.

Regional problem

The Arakan Project, a group advocating for the rights of Rohingya, has said as many as 8,000 people may be adrift.

Chris Lewa, the director of Arakan Project, told Al Jazeera that "there were at least three other boats near Langkawi island in Malaysia - one of them in distress" on Monday night.

She said that a big concern is where these migrants could go, and despite this being a regional problem, if there was any country willing to deal with them.

Earlier, the International Organisation for Migration called on Southeast Asian governments to find and rescue the migrants trapped at sea.

Joe Lowry, a spokesman for the organisation, told Al Jazeera that some of the migrants may have been at sea since early March.

He said that from what they've seen so far, many of the migrants who make it to the shore are in poor health, with some suffering from vitamin B deficiency and acute malnutrition.

The United Nations High Commissioner for Refugees (UNHCR) has said 25,000 people are believed to have embarked from January to March, double the previous year's pace, and that an estimated 300 had died.