The grisly find follows the discovery of similar shallow graves on the Thai side of the border earlier this month, which helped trigger a regional crisis. After a crackdown on the camps by Thai authorities, traffickers abandoned thousands of migrants in rickety boats in the Bay of Bengal and Andaman Sea.

The jungles of southern Thailand and northern Malaysia have been a major route for smugglers bringing people to Southeast Asia by boat from Myanmar, most of them Rohingya Muslims who say they are fleeing persecution, and Bangladesh.

“It’s a very sad scene… To us even one is serious and we have found 139,” Malaysia’s Inspector General of Police Khalid Abu Bakar told reporters at a news conference in the northern state of Perlis. “We are working closely with our counterparts in Thailand. We will find the people who did this.”

The graves, some of which contained more than one body, were found at 28 abandoned camps located within about 500 metres (550 yards) of the Thai border in an operation that began on May 11, Khalid said. The border area is rugged and desolate and there are few roads.

“The first team of our officers has arrived in the area this morning to exhume the bodies,” Khalid added.

He said one of the grave sites was just 100 metres or so from the site where twenty-six bodies were exhumed from a grave in Thailand’s Songkhla province in early May.

Smuggling crackdown

Thailand, under pressure from the United States to do more to combat people smuggling, launched a crackdown after finding that mass grave, since when more than 3,000 migrants have landed on boats in Malaysia and Indonesia.

The United Nations refugee agency UNHCR estimated on Friday, May 22, that some 3,500 migrants were still stranded on overloaded boats with dwindling supplies, and repeated its appeal for the region’s governments to rescue them.

On Sunday, Indonesia’s National Disaster Mitigation Agency said that starting next week, it would begin the repatriation of 720 Bangladeshi migrants over the next month.

The cost of the repatriation would be met by the UNHCR and the International Organization for Migration, said Sutopo Purwo Nugroho, spokesman at Indonesia’s disaster agency.Malaysian Prime Minister Najib Razak on Thursday, May 21, pledged assistance and ordered the navy to rescue people adrift at sea.Indonesia’s navy spokesman Manahan Simorangkir said it had deployed six ships and an aircraft last Wednesday to search for migrant boats.”They came back on Saturday and did not find any Rohingyas,” he said. “The ships and aircraft are back out again.”

Malaysian police said in a statement that two police officers were among 10 people arrested so far this year in investigations into human trafficking, without giving details.

Thailand said earlier this month that more than 50 police officers had been transferred as a result of investigations into human trafficking networks in the south.

Malaysia’s Najib said in a post on his official account that he was “deeply, deeply concerned with graves found on Malaysian soil purportedly connected to people smuggling.

“We will find those responsible,” Najib posted in English.