Police who received reports from members of the public about people carrying weapons and dressed in suspicious outfits said they were cosplay fans dressed up for an event.
Concerns were raised in Newcastle when someone was seen armed with a sword, Northumbria Police said.
After making inquiries, police reassured the public there was a cosplay event at St James' Park in the city.
Cosplay sees people dress up as characters from comics, books, films or video games to take part in arranged events.
On their Twitter account on Friday, police in Newcastle said: "This morning we have received a couple of reports from concerned members of the public who have seen people with
swords or suspicious outfits.
"We carried out the appropriate checks and found these individuals are attending a cosplay-style event at St James's Park today."
The reports were made in good faith, the force said.
They advised: "If you are planning on dressing up and carrying an item that may be mistaken as an offensive weapon, then we would advise you keep it in a bag until you arrive at the
"We want everyone attending these events to have a good time but in the light of recent events across the country it is important that people use their common sense."