LONDON (Reuters) - British police said on Tuesday they were hunting for 20 youths who seriously injured a Polish man in a suspected racially motivated attack, the latest in a number of hate crimes against eastern Europeans following the June vote to leave the EU.

The 28-year-old Pole was kicked and punched by a group of teenagers in the northern English city of Leeds, police said in a statement. The attack, which occurred on Friday night, left the man needing hospital treatment for a head injury.

Police said the incident was believed to be racially aggravated because of comments his attackers, a group of males aged 16 to 18, had made to the victim and his friend.

“I want to reassure people, particularly the local Polish community, that we will not tolerate hate incidents of this nature and will do everything we can to ensure the people responsible are brought to justice,” West Yorkshire police Chief Superintendent Paul Money said in the statement.

Money said officers were treating the attack as “an isolated incident and not as an indicator of any ongoing hate issue in the area”.

There was a surge in hate crimes across Britain in the wake of June’s referendum which saw Britons vote to exit the European Union with immigration one of the key issues.

At its peak, there was a 58 percent increase hike and police recorded more than 14,000 such crimes in the period running from a week before the vote to mid-August.

While offences decreased toward the end of August, the figures still showed a 14 percent rise compared to the same period last year. The rise lent support to anecdotal evidence of abuse toward Muslims and eastern Europeans following the referendum.

In August, six teenagers were arrested on suspicion of killing a Polish man in a suspected hate crime.