Merseyside Police said officers in Prescot, Knowsley, were dealing with two groups of protesters after a demonstration descended into chaos outside the Suites Hotel.
Knowsley MP Sir George Howarth said the demonstration was triggered by “an alleged incident on social media” and criticised misinformation claiming refugees were “feather-bedded” inside.
The force said a protest and counter protest in Ribblers Lane was initially peaceful, but during the evening there have been reports of missiles being thrown.
Videos shared on social media appear to show a police van on fire.
The force said there have been no reports of any injuries.
In a statement, it said: “Additional officers are in the area to deal with these incidents. We have also implemented a number of road closures on the East Lancs Road and would urge motorists to avoid the area and those in the area to disperse.”
In a statement, Labour MP Sir George said: “I have referred an alleged incident posted on social media, which has triggered a demonstration outside the Suites Hotel, to Merseyside Police and Knowsley Council.
“Until the police have investigated the matter, it is too soon to jump to conclusions and the effort on the part of some to inflame the situation is emphatically wrong.
“If an offence has been committed, the police should deal with it appropriately through due process.
“In addition, the misinformation about refugees being feather-bedded is untrue and intended to paint a picture that does not at all represent the facts.
“The people of Knowsley are not bigots and are welcoming to people escaping from some of the most dangerous places in the world in search of a place of safety.
“Those demonstrating against refugees at this protest tonight do not represent this community.
“We are not like that and overwhelmingly behave with sympathy and kindness to others regardless of where they come from.”
Merseyside’s Police Commissioner Emily Spurrell tweeted: “Deeply shocking and concerning scenes of violence in Knowsley this evening.
“Utterly unacceptable behaviour, putting officers and public in danger.
“I am monitoring the situation closely.
“There is absolutely no excuses for this.”