Texas synagogue siege: hostages safe and gunman dead after 10-hour standoff

All four hostages at a Texas synagogue have been released unharmed and the captor pronounced dead more than 10 hours after he disrupted a religious service and began a tense stand-off with police.

The gunman had initially taken four people, including the rabbi, hostage at the Congregation Beth Israel in Colleyville, in the Dallas-Fort Worth metropolitan area. One hostage was released unharmed six hours later.

Local reporters said they heard the sound of explosions, possibly flashbangs, and the sound of gunfire shortly before the Texas governor, Greg Abbott, announced the crisis was over.

It was not clear how the suspect might have armed himself.

The police department said it first responded to the synagogue with Swat teams in response to emergency calls beginning at about 10.41am and police arrived at about 12.30pm. FBI negotiators soon opened contact with the man, who said he wanted to speak to a woman held in a federal prison.

The incident took place during an online livestream of the Shabbat service at the synagogue. The livestream cut off at about 2pm local time.

In the livestream the hostage-taker was heard demanding the release of Aafia Siddiqui, a Pakistani neuroscientist suspected of having ties to al-Qaida, who was convicted of trying to kill US military officers while in custody in Afghanistan, one of the law enforcement officials said. Siddiqui is in federal prison in Texas.