The FBI identified a hostage taker killed at a Texas synagogue as a British citizen, after US President Joe Biden said the gunman had used weapons he got off the street to commit "an act of terror."
The FBI identified the man as Malik Faisal Akram, 44, who was killed after the safe release of his four hostages on Saturday night.
The incident in Colleyville, Texas, "was an act of terror," said Biden, who was in Philadelphia with first lady Jill Biden packing carrots and apples at a food bank in a visit to the city to honour the legacy of slain civil rights leader Martin Luther King Jr.
"Allegedly - I don't have all the facts, nor does the attorney general - but allegedly the assertion was he got the weapons on the street," Biden said.
"He purchased them when he landed and it turns out there apparently were no bombs that we know of. ... Apparently he spent the first night in a homeless shelter. I don't have all the details yet so I'm reluctant to go into much more detail," the president said.
Akram's family said it was "devastated" by his death, Sky News reported.
Akram's brother Gulbard said in a statement that family members had spent hours "liasing with Faisal" during the hostage-taking, and that although he was "suffering from mental health issues we were confident that he would not harm the hostages," Sky News reported.
The family said they "do not condone any of his actions and would like to sincerely apologise wholeheartedly to all the victims involved in the unfortunate incident," Sky reported.
An FBI Hostage Rescue Team on Saturday night stormed Congregation Beth Israel in Colleyville, about 26 km northeast of Fort Worth, ending a 10-hour standoff with police by the gunman, who disrupted a Sabbath service and took the rabbi and three other people hostage.
One hostage was released unharmed after being held for six hours and the remaining three were later safely freed by the FBI team.
SWAT teams from the Colleyville Police Department responded to the synagogue after emergency calls began at about 10:41 am during the Sabbath service, which was being broadcast online. FBI negotiators soon opened contact with the man, who said he wanted to speak to a woman held in a federal prison.
The man was heard having a one-sided phone conversation during a Facebook livestream of the service. The man could be heard ranting and talking about religion and his sister, repeatedly saying he did not want to see anyone hurt, the Fort Worth Star-Telegram reported.
The hostage-taker claimed to be the brother of Pakistani neuroscientist Aafia Siddiqui, who is serving an 86-year US prison sentence on her 2010 conviction for shooting at soldiers and FBI agents, and demanded that she be freed, a US official told ABC News.
Siddiqui is being held at a federal prison in the Fort Worth area. A lawyer representing Siddiqui, Marwa Elbially, told CNN in a statement that the man was not Siddiqui's brother and Siddiqui's family condemned his "heinous" actions.
Although the Texas hostage situation appeared to be an isolated incident, synagogues in New York and elsewhere around the country ramped up security in response and officials condemned anti-semitic acts.
"What happened yesterday at Congregation Beth Israel is a reminder that we must speak up and combat antisemitism and hate wherever it exists," US Vice President Kamala Harris said in a statement. "Everyone has a right to pray, work, study, and spend time with loved ones not as the other – but as us."