A militant leader and two of his aides were hanged for a grenade attack on the British ambassador in 2004.
Bangladesh hanged three extremists including the leader of a banned militant outfit and two of his aides on Wednesday, after they were sentenced to death over a 2004 grenade attack on the British ambassador.
Mufti Abdul Hannan, the head of Harkatul Jihad Al Islami (HuJI) and two associates were convicted and sentenced to death in 2008 over the carnage, with Bangladesh's highest court upholding the sentences last month.
Their attack on a Muslim shrine in the northeastern city of Sylhet killed three people and wounded the then-British high commissioner.
"They were hanged at 10 pm (1600 GMT) in two prisons," senior superintendent of the Kashimpur Central Jail, Mizanur Rahman, said.
Hannan and the two associates, Delwar Hossain and Sharif Shahedul Islam, sought clemency from the Bangladeshi president in a last-ditch attempt to commute the execution orders to life sentences, but he rejected their pleas.
New York-based Human Rights Watch had asked the government to halt the executions of the three militants, saying evidence against them was based on confessions possibly extracted through torture.
With the latest executions, at least ten extremists have been hanged by Prime Minister Sheikh Hasina's secular government since 2013.