​Arsenal's Europa League opener against German side Cologne has been pushed back an hour due to concerns over crowd safety.

Thousands of fans bearing no tickets showed up outside of the Emirates and no supporters have been allowed in.

"The kick-off of #AFCvCOL has been delayed by an hour in the interests of crowd safety," the Gunners' official Twitter account posted.

The away supporters only had 2,900 tickets to share among themselves, yet over 20,000 of them stormed the capital earlier on Thursday to back their team.

Reports claim that flares have been let off, but so far, there has been no real disorder in the large crowd.