Police in Rome say seven men were injured. Five were British, one Californian and one Bangladeshi.
A group of about 40 or 50 people in motorcycle helmets or with their faces covered were armed and attacked the group of English football fans drinking in Campo de Fiori square. The more seriously injured seems to be the Briton born in 1987. The American was born in 1982.
More top news
The FA said almost 4,000 fans were present at the Nizhny Novgorod Stadium.
Harry Kane's hat-trick inspired England to their biggest ever World Cup win as they sealed progress to the last 16 beating Panama 6-1
The duke was warmly welcomed by Al Hussein bin Abdullah II in Amman.