Football fans at today's Community Shield clash in Cardiff are being asked to be vigilant by police following the recent terrorist attacks in London.
Despite being no specific terrorist threats in south Wales thus far, the Millennium Stadium is believed to be one of a number of locations under review to step up security.
Over 60,000 fans attending the game today will have their bags searched as they enter the stadium to watch FA Cup winners Arsenal take on Premiership champions Chelsea.
And Cardiff Chief Superintendent Bob Evans is asking fans to tell police if they see anything suspicious.
"There is no direct intelligence in relation to the match, but we are not going to be complacent about it," said Evans.
"But we are increasing security because at the end of the day there is a general national and international risk."
Police will be stepping up CCTV surveillance in the city centre and extra officers are to be posted at the various major train and bus stations.
"Surveillance will look at skips, abandoned vehicles and bins. There won't be more officers inside the stadium but we will have extra police and community support officers based around the stadium.
"We will focus our patrols at key points such as the rail and bus stations to reassure people and look out for anything suspicious."