Prime Minister Shinzo Abe on Sunday expressed anger over the terrorist attack in Bangladesh that claimed the lives of 28 people, including two Japanese women and five men who had voluntarily offered their expertise for a government development project.

"This is deeply regrettable. I am at a loss for words when I think of how unfortunate this was for the victims," Abe said. "This is an unforgivable act of terrorism."

Most of those killed in the bloody hostage crisis at an upscale restaurant in Dhaka were foreigners who were apparently hacked to death by militant extremists. The Islamic State group later claimed responsibility for the attack.