Officers evacuated the synagogue’s surroundings and cordoned off the area, the police force said.

ABC News reported that the hostage-taker was armed and had claimed to have bombs in unknown locations. That was not confirmed by police although Colleyville Police Chief Michael Miller said that “bomb techs are clearing the scene.”

Quoting a US official briefed on the matter, ABC reported the man was demanding the release of Aafia Siddiqui – a Pakistani scientist who in 2010 was sentenced by a New York court to 86 years in prison for the attempted murder of US officers in Afghanistan.

She is currently being held at Federal Medical Center (FMC) prison in Fort Worth, Texas.

Mr DeSarno told the news conference the suspect had been identified, but did not disclose his identity. He added that the investigation is ongoing and they will be working with police in London on the case. 

Officials said they have identified the suspect, but will not release his name yet or motive, but said they were “focused on one issue that was not specifically threatening to the Jewish community” – and that he did not believe there was an ongoing threat.

‘Aafia Siddiqui condemns attack’

ABC initially said the man claimed to be Siddiqui’s brother, but later clarified her brother is in Houston – while other experts said the word the man used in Arabic was more figurative and meant “sister” in the Islamic faith.

Siddiqui’s lawyer said she “has absolutely no involvement” in the hostage situation in a statement to CNN. The lawyer confirmed that the man was not Siddiqui’s brother and said she condemned his actions.

Lawyer Annette Lamoreaux who represents Siddiqui’s biological brother Mohammad, a Houston architect, told Mail Online: “The gunman is most definitely not her biological brother.”

“I spoke to Mohammad an hour ago and he is very upset to be implicated in this attack by the hostage-taker.” 

Mr DeSarno said police negotiators “had a high frequency and duration of contact with” the hostage-taker.

“There were times when it stopped for periods of time and like many hostage situations, the relationship between the negotiators and hostage-taker had been floating a little bit and sometimes got intense,” he said.

A live stream of the congregation’s Shabbat morning service, available on Facebook for around four hours during the standoff, appeared to capture audio of a man talking loudly – although it did not show the scene inside the building.

In it, 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.”

Beth Israel congregation member Ellen Smith, who grew up going to the synagogue, described the situation as “shocking and horrifying” in a CNN interview.