At least 30 mass graves believed to contain the bodies of hundreds of Rohingyas and Bangladeshis, have been found near Malaysia's border with Thailand.
The discovery of migrants' mass graves follows the similar graves in Thailand early in May.
Quoting the Mingguan Malaysia newspaper, South-East Asia correspondent for Fairfax Media Lindsay Murdoch reported that graves were found in mid-May in forests in Padang Besar and Wang Kelian.
File photo of mass grave found earlier in Thailand
Malaysian police are determining whether the graves were of human trafficking victims, Home Minister Ahmad Zahid Hamidi said.
He, however, did not say how many dead bodies were discovered.
"This is still under investigation," Reuters quoted the minister.
Several foreigners and local villagers had been arrested under anti-trafficking and anti-smuggling laws, according to the report published in the Sydney Morning Herald.
“So far, no details are available as it is believed police are in the middle of conducting the operation,” The Star quoted a source.
Quoting a police officer at the Padang Besar district police headquarters, it reported that the location was a restricted area, which is not accessible to civilians.
“The place has been cordoned off and it is located at a hilly site,” he said.
For years Malaysia has quietly allowed tens of thousands of Rohingyas and Bangladeshis who had been smuggled into the country by human traffickers, according to the Sydney Morning Herald report.
Many of the trafficked migrants had been held in jungle camps and in boats at sea while traffickers demanded ransoms from their families.
Twenty-six bodies were exhumed from a grave in Thailand's Songkhla province, over the border from Perlis, near a camp with suspected links to human trafficking.
More than 3,000 migrants, most of them from Myanmar and Bangladesh, have landed on boats in Malaysia and Indonesia this month after a crackdown on trafficking in Thailand.
Malaysian Prime Minister Najib Razak on Thursday pledged assistance and ordered the navy to rescue thousands adrift at sea.