Police in Ballymena, about 30 miles northwest of Belfast in County Antrim, said they are looking for a masked man who attacked two women early Tuesday while they walked near a highway, UTV News reported.
Authorities said the man was armed with a knife and a baseball bat and attacked from behind, hitting one of the women, a foreign national in her 60s, several times in the head with the bat.
She required hospitalization, while the other woman -- also a foreign national said to be in her 40s -- escaped the incident uninjured.
The Police Service of Northern Ireland appealed to the public for information about the incident.
The attack came only hours after Ballymena was the scene of sectarian violence, triggered by a decision taken last month regarding flags flown at Belfast City Hall, that flared through Northern Ireland.
A majority of city councilors in December voted to fly the British flag only on certain days rather than year round, sparking outrage from loyalists and sporadic violence in Ulster.
More than 60 police officers have been injured in flag-related unrest since the decision, with around 100 people arrested, The Irish Times reported.
The clashes escalated Monday when loyalist demonstrators returning from city hall had objects thrown at them from a nearby nationalist neighborhood.
Before the incident, loyalists staged a protest march in Belfast's city center, forcing police to close roads and disrupt traffic in the commercial area.
In Ballymena, clashes broke out in the same area as Tuesday's apparent hate crime.
The latest incident brought a condemnation from Robin Swann, Ulster Unionist Party member of the Legislative Assembly from Antrim.
"I was shocked to learn that two women were subjected to a violent attack by a man with a baseball bat in the Larne Link Road area of Ballymena at around 2 a.m. on Tuesday morning," he said.
"Clearly the individual responsible is a danger to the public and must be stopped. I appeal to anyone with any information to come forward immediately and assist the police."
Loyalists said they were shocked at the decision to restrict the display of Union flag at city hall, which was taken by a city council majority comprised of the nationalist Sinn Fein and Social Democratic and Labor parties as well as the non-sectarian Alliance Party.
Every unionist council member voted against the change.
Politicians from all parties since then have received death threats, including a bullet and sympathy card mailed to SDLP Assembly Member Patsy McGlone, the newspaper said.
At a council meeting Monday, Sinn Fein's Jim McVeigh declared he wouldn't be swayed by threats or protests.
"Their protests are pointless and they will have absolutely no impact on decisions that we take," he said, adding that while nationalists would respect British tradition, that respect was "not one way."