In this photo taken on February 11, 2023 a police van is seen parked outside the closed gates of the Suites Hotel near Liverpool in north-west England where an anti-immigration protest was staged by far-right protesters outside the hotel for housing asylum seekers. AFP
Clashes broke out when troublemakers disrupted a pro-refugee gathering outside a hotel housing asylum seekers near Liverpool, police said.
A far-right, anti-immigrant group had protested outside the same hotel earlier this month.
The open letter, co-ordinated by coalition campaign Together With Refugees and signed by 180 charities, condemned the "horrifying" scenes on Friday outside the hotel near Liverpool, in northwest England.
Merseyside Police arrested 15 people after fireworks were thrown at officers and a police van was attacked with hammers and set alight during several hours of mayhem.
One of those arrested, a 19-year-old man, appeared in court on Monday charged with violent disorder and assault for beating an emergency services worker.
"With the high risk of more premeditated extremist attacks around the country, leaders of all parties must now take a clear stand and condemn any further violence against those who come here to find safety," the charities' letter stated.
It also urged political leaders to "set out the action they will take to prevent it".
Hardline interior minister Suella Braverman has faced sustained criticism for her inflammatory rhetoric over immigration, in particular her description of the growing number of migrants crossing the Channel.
Opponents accuse her of demonising asylum seekers and fuelling hostility towards people seeking sanctuary.
In November, she sparked an outcry by saying in parliament that England's south coast was facing an "invasion" of illegal migration.
Tens of thousands of people arrived in southeast England on small boats from the European mainland last year, dramatically increasing a trend that began on a large scale in 2018.
A spokesperson for the interior ministry noted that Braverman had condemned the "appalling scenes outside the hotel and violence toward police officers" seen on Friday.
"The welfare of asylum seekers in our care is of the utmost importance and we will work with the police to ensure their safety," the spokesperson added.
Friday's violence in Merseyside erupted when troublemakers came to a planned demonstration by refugee advocacy groups outside the hotel, police said.
The far-right group Patriotic Alternative had protested outside the hotel earlier this month, although the group denied it was the organiser of the latest rally.
Police linked the protest to social media and rumours that a man had made "inappropriate advances" to a 15-year-old girl in the area, saying this was used as "an excuse to commit violence".