Six teenagers have been arrested on suspicion of killing a Polish man in a possible hate crime.
Arkadiusz Jozwik, 39, was left with head injuries after an unprovoked attack in Harlow, Essex, on Saturday night. He died on Monday evening.
His friend, a 43-year-old man, suffered hand and stomach injuries.
Harlow MP Robert Halfon said the killing would be "all the more disturbing and shocking" if it turned out to be a hate crime.
Five 15-year-old boys and one 16-year-old boy, all from Harlow, were arrested on suspicion of murder. All but one 15-year-old have been bailed.
In a statement published on Twitter, the Polish Embassy said it had been "shocked" by Mr Jozwik's death, and was liaising with Essex Police.
Ambassador Arkady Rzegocki visited The Stow, where the attack happened, to lay flowers, telling the media his country and the UK must show solidarity in the wake of the death.
"We are shocked but we are also thankful for local support since the attack," Arkady Rzegocki said, as he stood with Mr Halfon.
"Poles have been present in Britain for centuries, and I hope this never happens again."
Mr Halfon said he had been contacted by some Polish members of the community who were "incredibly scared and upset at what has happened".
"I give my heartfelt sympathy, not just to these men's families and friends, but to the whole of Harlow's wonderful Polish community," he said.
The MP added he has contacted Essex Police's chief constable to ask what measures were being taken "to protect our communities, particularly those who are ethnic minorities or migrants".
A 48-hour dispersal order has been granted to police and will be in place from 19:00 BST on Wednesday.
It means officers can order anyone to leave the area if they have reasonable grounds to believe the person is harassing residents or likely to be involved in crime or disorder.
Supt Andy Mariner said: "Over the last two months we have received reports of nuisance and anti-social behaviour in The Stow, which have affected the quality of life for residents and shop owners.
"These complaints relate to groups of youths congregating in the area, riding bikes and motorbikes and generally acting in an anti-social manner.
"In our discussions with the public we have been made aware of further incidents of anti-social behaviour that had not been previously reported to us."
Harlow has one of the highest concentrations of EU nationals from eastern Europe, roughly one in 17 residents, according to figures from the Office for National Statistics.
The town is in the top 30 local authorities in England and Wales with the greatest proportion of eastern European nationals.
Ivona Schulz-Nalepka, director of Harlow Polish School, said: "Some people in the Polish community are frightened about what happened.
"The is the first time something as serious as this has happened in Harlow so of course we are worried."
Jacek Gora, who runs a Polish shop in Harlow, has started collecting signatures on a Polish flag from people who knew Mr Jozwik.
"For everyone it's really strange, as he was the quietest person... He was a really good guy," Mr Gora said.
"Everyone wants to help. All the Polish shops in the town centre are doing this."