Police closed off a junction of a major Bootle road after reports of shots being fired.
There was a large police presence at the junction of Southport Road and Bedford Road at around 8.30pm on Saturday.
Residents reported seeing the police helicopter overhead as the emergency response got under way.
They said they believed police were responding to reports shots had been fired, in what appears to be the latest reported gun crime incident to hit Merseyside.
It comes after a man was shot in Tower Hill, Kirkby, on Friday night.
There is no suggestion at this stage that the incidents are linked.
One eyewitness to the Bootle scene, who did not wish to be named, said: "Police were suddenly here in big numbers and had the tape up. They seemed to be focusing on quite a wide area around the traffic lights.
"Traffic seemed to still be getting through but drivers were slowing down and stopping to see what was going on.
The ECHO understands no one was believed to have been hurt in tonight's incident.
Anyone with information should contact police on 101 or Crimestoppers on 0800 555 111.
