Football thugs trying to fly to Portugal for Euro 2004 from the North West are "wasting their time", police have warned.
Uniformed and plain clothed officers started patrolling Liverpool and Manchester airports on Monday.
"I strongly suggest that they don't attempt to get to Portugal as they will be wasting their time," said DC Steve Chisnall of Greater Manchester Police.
The moves are part of a national crackdown for the tournament.
Members of the football intelligence units from the Greater Manchester and Merseyside forces will be on
the lookout for people trying to breach the ban imposed for the duration of the championships.
DC Chisnall said smaller and successful operations had been in force for other England fixtures in the past year.
"This operation is larger in scale, but we envisage
the results will be the same," he said.