A hostage-taker who detained four people at a synagogue in a suburb of Dallas, Texas, was a British citizen, reports say.

The man interrupted a morning service in Colleyville on Saturday and has since died.

The four people taken hostage included the synagogue's rabbi, according to US media reports.

A live stream of the Shabbat morning service on Facebook captured audio of a man talking loudly.

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.

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?

Texas synagogue hostage-taker was British – reports.