A man who took four hostages at a synagogue in a suburb of Dallas, Texas, has been identified by the FBI as British citizen c, 44.
The man who interrupted a morning service in Colleyville on Saturday died after a 10-hour standoff with police during which explosions and gunfire could be heard.
All of the hostages at the Congregation Beth Israel were freed unharmed.
US President Joe Biden called the hostage-taking an “act of terror”.
There is currently no indication that others were involved, the FBI in Dallas said.
Negotiators had spent hours talking to the assailant during the standoff.
The UK Foreign Office said it was aware of the death of a British man in Texas and was in contact with the local authorities.
The four people taken hostage included the synagogue’s rabbi. One was released after six hours with the other three being led to safety by police several hours later.
The incident began at around 11:00 local time (16:00 GMT) when police were called to the synagogue. People were evacuated from the area shortly after.
A live stream of the Shabbat morning service on Facebook captured audio of a man talking loudly. He could be heard saying: “You get my sister on the phone” and “I am gonna die.”
He was also heard saying: “There’s something wrong with America.” The feed was later taken down.
The hostage-taker was heard demanding the release of Aafia Siddiqui, a Pakistani neuroscientist who is currently serving an 86-year prison term in the US, law enforcement officials told local media.
Siddiqui was convicted of trying to kill US military officers while in custody in Afghanistan. Thousands took to the streets in Pakistan to protest against her conviction in 2010.
President Biden appeared to confirm the attacker had been seeking her release, saying the Texas attack was related to “someone who was arrested 15 years ago and has been in jail for 10 years”.
After the Islamic State (IS) group kidnapped American journalist James Foley in Syria in 2012, they emailed his family demanding the release of Siddiqui.
A lawyer representing Siddiqui told CNN in a statement that the hostage-taker was not her brother, saying Siddiqui’s family condemned his “heinous” actions.
Texas resident Victoria Francis, who was watching the live stream before it cut out, told the Associated Press that she heard the man rant against America and claim he had a bomb.
“He was pretty irritated and the more irritated he got, he’d make more threats,” she said.