Woman, 97, was among 11 killed in the Pittsburgh Tree of Life Synagogue shooting

Other victims include Rose Mallinger, 97, Joyce Feinberg, 75, Rich Gotfried, 65, and Jerry Rabinowitz, 66.

Melvin Wax, 88 and Irving Youngner, 69, were also named by officials in a press conference on Sunday. 

The suspect, 46-year-old Robert Bowers, is accused of entering the synagogue, which is in the city's Squirrel Hill neighbourhood, at around 10am local time.

As well as those killed, many others were injured, including four police officers.

The suspect, who eventually surrendered to police following a shootout, had reportedly shouted "all Jews must die".

Anti-Defamation League President Jonathan Greenblatt said: "This is likely the deadliest attack on the Jewish community in the history of the United States...

"It is simply unconscionable for Jews to be targeted during worship on a Sabbath morning, and unthinkable that it would happen in the United States of America in this day and age."

President Donald Trump, who said he would visit Pittsburgh soon, described the attack as a "wicked act of mass murder".

He ordered US flags at government buildings to be flown at half-mast until October 31.

He told reporters: “To see this happen again and again, for so many years, it's just a shame.

He said the US should "stiffen up our laws of the death penalty".

"These people should pay the ultimate price. This has to stop.”