A member of Bangladesh's ruling party was found murdered in the Indian city of Kolkata on Wednesday morning, more than a week after he went missing, Bangladeshi Home Minister Asaduzzaman Khan said.

Anwarul Azim Anar, from the Awami League party, went missing on May 13, a day after going to India to seek medical treatment, according to his relatives.

Asad Khan told reporters in Dhaka that three Bangladeshis had been arrested over the death. "We cannot disclose all information at the moment for the sake of the investigation," the minister added. 

"Awami League MP Anwarul Azim Anar, who went missing in India, was murdered at a Kolkata flat," Khan told reporters. "So far, we have come to know that all the killers involved are Bangladeshis. It was a planned murder," he said.

The minister said that Bangladesh Police have arrested three persons in connection with the murder of the 56-year-old lawmaker, The Daily Star reported.

Asked about the whereabouts of the body, he said that they were yet to know about it. "We will soon inform you about the motive," the minister said, adding that Indian police are cooperating with the case.

The three-time MP and president of Kaliganj Upazila unit Awami League went to India on May 12 on a personal visit to receive treatment.

A general diary report about his disappearance was filed at Baranagar Police Station in North Kolkata on May 18, the report said.

Bangladesh Prime Minister Sheikh Hasina has expressed deep shock and sorrow at the death of Azim, the portal said quoting the United News of Bangladesh news agency.

Azim was the AL lawmaker from the Jhenaidah-4 constituency. "Jhenaidah is a bordering area known for its high crime rate. Azim was the local lawmaker there. The incident took place after went to India for treatment. According to what we currently know, he was killed there," the minister said.