A university professor was brutally murdered in Bangladesh in the latest attack on liberal activists by suspected Islamist militants, local police have said.

Police official Golam Sackline said at least two people on a motorcycle had ridden up to Rezaul Karim Siddiquee, an English professor at Rajshahi University, before he was brutally hacked to death.

He said the pattern of the murder was similar to a string of recent violent attacks by Islamist militants in the country, targeting members of minority Muslim sects, liberal activists and other religious groups.

"We are investigating the killing," he added.