Counter-terror police are urging football clubs to issue security advice to fans at the start of the Premier League season, amid fears stadiums could be targeted.
A senior police officer said terrorists are prepared to attack events such as football games, although there is no specific intelligence of an increased threat to grounds.
The warning comes after four UK terror attacks this year, including a suicide bombing in the Manchester Arena, which left 22 dead and 59 injured.
Officials from clubs across the country attended two police workshops, held at Wembley and Old Trafford, designed to address the threats to sports grounds.
Superintendent Dave Roney, the deputy national coordinator for the "Protect and Prepare" counter-terror strategy said the events allowed clubs to share best practice and gave police an insight into match days.
"While there is no specific intelligence of an increased threat to football grounds in the UK, we have seen that terrorists are prepared to carry out attacks on this type of target," he said.
"We have been pleased with the response from the football authorities in attending our events and making renewed efforts to do all they can to keep supporters safe."
Both the Premier League and the EFL have committed to circulating security advice to all clubs to use on their websites and social media streams.
Supporters will be told to arrive early to games and minimise what they carry, as bag searches can slow entry to grounds.
Fans will also be urged to remain vigilant, and to evacuate immediately if told to do so rather than waiting around to film on mobile phones.