Bangladesh hanged three Islamist extremists including the leader of a banned militant outfit on Wednesday, after they were sentenced to death over a 2004 grenade attack on the British ambassador.
The explosion at a 14th century Sufi shrine in the northeastern city of Sylhet killed three people and injured the British high commissioner at the time.
Mufti Abdul Hannan, the head of Harkatul Jihad Al Islami (HuJI) and two associates were sentenced to death in 2008 over the carnage, with Bangladesh's highest court upholding the sentences last month.
"They were hanged at 10 pm (1600 GMT)," Home Minister Asaduzzaman Khan told AFP.
Hannan and the two associates, Delwar Hossain and Sharif Shahedul Islam, sought clemency from the Bangladesh President in a last-ditch attempt to commute the execution orders to life sentences, but he rejected their pleas.
A madrassa teacher who studied in India and Pakistan, Hannan, 60, fought against the Soviets in Afghanistan before returning to join HuJI, a group founded for jihadists who fought in that war.
-- Deadly attacks --
Prosecutors said Hannan had headed HuJI since the late 1990s, masterminding deadly attacks on a church, secular gatherings, and mosques used by Islam's minority sects.
In August 2004, in one of the country's deadliest extremist attacks, he masterminded the blasts at a political rally of current Prime Minister Sheikh Hasina outside her party office in central Dhaka.
Hasina, then leader of the opposition, narrowly survived what she said was an assassination attempt. At least 22 people were killed and more than 100 were injured.
By the time Hannan was arrested in late 2005, more than 100 people had been killed in attacks he orchestrated across the Muslim-majority nation.
HuJI was the first Islamist militant outfit to emerge in Bangladesh, and rose to prominence as Hannan escalated its deadly operations under his leadership.
Security was tight at the Kashimpur high security prison, where Hannan and Shahedul Islam were hanged, and at Sylhet jail where Hossain was executed, with hundreds of policemen and an elite security force patrolling outside the facilities.
Last month suspected Islamist extremists hurled bombs at a prison van in a daring attempt to free Hannan near the Kashimpur jail. Police arrested a 24-year-old former Madrassa student at the scene.
-- Islamic State group --
Tension is running high in the moderate Muslim country in recent weeks following a resurgence of extremist attacks, with at least three being claimed by the Islamic State group.
The fatalities included the head of intelligence of an elite security force tasked with tackling Islamist militancy across the Muslim-majority country.
Al-Qaeda and the IS have claimed responsibility in dozens of attacks in recent years, but Hasina's secular government blames local outfits, mainly another banned group, Jamayetul Mujahideen Bangladesh.
Police and army commandos have arrested scores of suspected extremists and killed more than 60 people since an attack on a Dhaka cafe last year that left 22 people, most foreign hostages, dead.
New York-based Human Rights Watch had asked the government to halt the executions of the three extremists, saying evidence against them was based on confessions possibly extracted through torture.
With the latest executions, at least ten Islamists have been hanged by Hasina's secular government since 2013.