An attack on two Polish men hours after a remembrance march for one of their compatriots who was killed in the same town is being investigated as a potential hate crime.

One of the men suffered a cut to his head and the other had his nose broken in an assault by a group of four of five men at about 3.30am in Harlow, Essex, on Sunday. Both men were treated at Princess Alexandra hospital before being discharged.

Two Polish men assaulted in potential hate crime on Kitson Way in #Harlow at around 3.35am today. Witnesses call 101 pic.twitter.com/8CTwuZvqay — Essex Police (@EssexPoliceUK) September 4, 2016

The attack came a week after Arkadiusz Jóźwik, 40, was knocked unconscious outside a row of takeaway shops on The Stow in Harlow. Jóźwik, whose brother said the assault began after the factory worker was heard speaking Polish, died later in hospital.

The killing, which is also being investigated as a possible hate crime, raised fears about an upsurge in hate crime targeted at eastern Europeans following Britain’s EU referendum. As a result, the Polish community held a “march of silence” through the town on Saturday.

Silent march in #Harlow in memory of Arkadiusz Józwik. United against violence and hate. #PolesinUK pic.twitter.com/bFoWghWs9b — Polish Embassy UK (@PolishEmbassyUK) September 3, 2016

The attack in the early hours of Sunday morning, which took place outside the William Aylmer pub on Kitson Way, is likely to increase their concerns.

Supt Trevor Roe, from Essex police, said of the latest incident: “This was a vicious and horrible attack. Although we are considering this matter as a potential hate crime, it is not being linked with the attack at The Stow last weekend. I want to reassure the public and the community in Harlow we are treating this very seriously and do not tolerate assaults of any kind.

“Harlow is a strong and resilient community, but I understand the concerns that recent events will cause. There will be an increased number of visible policing patrols in Harlow to both reassure and protect the community.”

He said the attack took place in a busy area in the town centre and appealed for witnesses to come forward.

Five 15-year-old boys and one 16-year-old boy, all from Harlow, have been arrested on suspicion of murdering Jóźwik and bailed until 7 October pending further inquiries.

At Saturday’s march, the Polish ambassador to the UK and the local MP, Robert Halfon, laid flowers at the site of the killing. Halfon has described it as “not just a tragedy for the family or for Poland [but] ... a tragedy for Harlow and Britain as well”.

There was a rise in the number of hate crimes around the 23 June referendum. More than 3,000 allegations of hate crimes were made to UK police, mainly in the form of harassment and threats, in the week before and the week after the vote, a year-on-year increase of 42%.