Police in Liverpool have been dealing with a number of "isolated outbreaks" of disorder, including reports of vehicles on fire and criminal damage.
Merseyside Police said a number of officers were deployed to the south of the city after being called to reports of disorder at 22:00 BST on Monday.
Members of the public are being asked to avoid several roads in the area.
There have been reports of objects being thrown at riot police and their vans.
The trouble came after a third day of violence across London, which followed a fatal police shooting last week.
There were also reports from an eyewitness of up to 200 youths wearing masks in Toxteth.
A section of High Park Street was blocked by police with vans and officers wearing riot gear as a group of youths gathered in Dingle.
A police helicopter circled the area.
There were reports of a 10-minute stand-off in Admiral Street, with youths throwing bottles, cans and sticks at riot police.
The youths eventually dispersed into three separate groups.
Assistant Chief Constable Andy Ward said: "Officers have tonight dealt with a small number of incidents of violence across the city.
"We will not tolerate any violence on the streets of Liverpool and have taken swift and robust action in response.
"We will work hard to ensure the people involved in the incidents are brought to justice.
"Merseyside Police has good links with communities across the region and over the last two days we have worked closely with residents to assess tensions within the community.
"We will continue to work with community leaders across the region to ensure an appropriate response to any incidents that occur."
Members of the public were told to avoid the Smithdown Road, Upper Parliament Street, Lodge Lane and Lawrence Road.