Machete-wielding assailants hacked to death a village doctor and wounded a university teacher in Bangladesh on Friday, in what police suspected was the latest in a series attacks by Islamists in the majority-Muslim nation.

The attackers rode a motorcycle, which they used to block the victims' motorcycle in the western district of Kushtia, 245 km from Dhaka, said district police chief Mohammad Sahabuddin Chowdhury.

The homeopathic doctor, Mir Sanaur Rahman, 55, was killed on the spot, and his companion, identified as Saifuzzaman, 45, suffered serious wounds. Police found a bloody machete at the scene.

"We suspect Islamist militants are behind the attack," Chowdhury said.

Police were checking whether the victims had any particular enemies or if other factors could have been a motive but media reported associates of the doctor saying he had a reputation for progressive views. Friends of the wounded university teacher said he too was known for being progressive-minded.

The doctor was on his way to a weekly free clinic he operated when he was attacked.

Over the past year, the South Asian nation of 160mn has seen a surge of attacks on atheist bloggers, academics, members of religious minorities and foreign aid workers.

At least 26 people have been killed including five secular bloggers, a publisher and two gay right campaigners have been among those milled since February 2015.

Al Qaeda in the Indian Subcontinent has claimed some of the attacks. Members of Islamic State have also claimed responsibility for some attacks, including the killings of two foreigners last year, and a university professor and a Hindu last month.

The government has denied that Islamic State or al Qaeda groups have a presence in the country and says home-grown Islamists are responsible.

Police have announced 1.8mn taka ($23,000) rewards for information leading to the arrest of six militants of a banned home grown group called Ansarullah Bangla Team, which is believed to be behind the killing of the bloggers.