Bangladesh executed an Islamist militant leader and two of his aides on Wednesday for a grenade attack on the British ambassador in 2004, a senior prison official said, days after the president turned down their clemency pleas.

The Supreme Court last month upheld death sentences for the three militants. Their attack on a Muslim shrine killed three people and wounded the then-British high commissioner .

Mufti Abdul Hannan, the head of the banned Harkat-ul Jihad Islami group, Sharif Shahedul and Delwar Hossain were convicted and sentenced to death in 2008 for the attack, which took place on May 21, 2004, after Friday prayers in the northeastern district of Sylhet.