Update 4pm: Detectives investigating the murder of a Japanese man during a series of random attacks in Dundalk, Co Louth have said terrorism is one line of inquiry.

An 18-year-old Egyptian man has been arrested on suspicion of the knife murder and subsequent assaults on two local men - one with a knife and one with a fence pole.

Gardai have not established a definite motive for the violent spree in the Avenue Road area around 9am this morning, but Chief Superintendent Christy Mangan said a potential terror link was being investigated.

He said this morning’s attacks in Louth appear to be "random and unprovoked".

The first of these attacks happened at 9am this morning when a 24-year-old Japanese man was stabbed on Avenue Road in Dundalk.

He died from his injuries.

About half an hour later emergency services were alerted that another man had been stabbed at Coes Road.

The scene of the fatal attack on Avenue Road, Dundalk this morning. Pic: Colin Keegan, Collins

Another man was attacked with a pole at Seatown Place just minutes later.

A member of An Garda Síochána then saw a man carrying a pole and behaving in an erratic manner nearby on Inner Relief Road.

"A terror attack is a line of inquiry," said Chief Superintendent Christy Mangan.

"It is certainly a line that we would look at. We will endeavour to establish the suspect's background, who they are and where they have come from and why are they here.

"Those are the very important questions we are endeavouring to ask and answer. And as to why the attacks took place, why an innocent bystander going about their work would be attacked in the middle of Dundalk in the morning slightly before 9am."

The scene of the fatal attack on Avenue Road, Dundalk this morning. Pic: Colin Keegan, Collins

Mr Mangan declined to confirm whether a potential mental health link was another line of inquiry.

He said the suspect had come into contact with gardai on January 1 when inquiries about his immigration status were conducted.

The senior officer said he believed the teenager was seeking asylum in the Irish Republic.

Gardai are unsure how long the suspect has been in Ireland.

He is being held at Dundalk Garda Station this evening and can be questioned for up to 24 hours.

The series of attacks started when the Japanese man was fatally stabbed on Avenue Road shortly before 9am.

Chief Superintendent Christy Mangan speaking at Dundalk Garda Station. Photo: Colin Keegan, Collins Dublin

An Irish man was stabbed a short time later on nearby Coes Road. At 9.40am gardai received a report that another local man was attacked with a fence pole at Seatown Place. Neither of the two Irish victims sustained serious injuries.

The suspect was arrested at around 9.45am on Inner Relief Road in Dundalk. He has been detained at Dundalk Garda Station.

Mr Mangan said he believed the perpetrator was on foot and the victims were selected at random.

"There is nothing to suggest whatsoever that any of these people involved in the attack and the subsequent assaults were known to each other," he said.

"It would certainly appear to be random and unprovoked."

He said there was no evidence that anyone assisted the attacker.

Mr Mangan said gardai were making efforts to contact the dead man's relatives.

"It is going to be very, very hard for the family," he said.

"They have someone over here working and the next thing they get attacked and killed in a foreign country."

He said the investigation would have an international dimension and gardai would be liaising with the authorities in Egypt.

Fianna Fáil Spokesperson on Justice Jim O’Callaghan said: "Minister for Justice Charlie Flanagan needs to clarify as to what extent this person was known to the authorities, what his status in the country was and whether he traveled to another EU country prior to his arrival in Ireland."

Councillor Ruairi O Murchu lives close to the scene of the attack in Avenue Road.

He said there was major concern among local people.

"The community is in shock," said the Sinn Fein representative.

"Our thoughts are with the family of the person killed and those that have been injured."

Update - 1.09pm: Gardaí are trying to establish a motive for a number of stabbings in Co. Louth.

A 24-year-old man has been killed and two others injured in the attacks in Dundalk.

An 18-year-old man, originally from Egypt, has been arrested.

Just before 9am this morning, a 24-year-old Japanese man was attacked and stabbed on Avenue Road in Dundalk. He was pronounced dead at the scene.

Two other people - believed to be Irish - were subsequently stabbed or assaulted nearby but the extent of their injuries are not known.

Two sniffer dogs have been examining the scene on Avenue Road.

12.09pm: Man stabbed to death in Dundalk, two others injured

Gardaí have confirmed that two other people have been injured in an attack in Dundalk in which a man was stabbed to death this morning.

The victim of this attack is understood to be Asian and was stabbed just before nine this morning on Avenue Road in Dundalk, Co Louth.

Two other people were also hurt in the stabbing but the extent of their injuries are not known.

A man, believed to be from the Middle East, has been arrested and brought to Dundalk Garda Station for questioning.

Gardaí are now working to try establish a motive for this stabbing and if the victims knew the attacker each other or if it was a random attack.

10.05am: Man stabbed to death in Dundalk, others injured

Gardaí say they are at the scene of a fatal stabbing in Co Louth.

Thay have said a man was been pronounced dead at the scene of the incident in Dundalk which happened shortly before 9am this morning.

They also said a number of other people were injured in the incident.

One man has been arrested and is being held in Dundalk Garda Station.

Officers are preserving three scenes for technical examination: Avenue Road, Inner Relief Road and Seatown.

Investigating Gardaí are appealing for witnesses to contact Dundalk Garda Station on 042 9388400, the Garda Confidential Line 1 800 666 111 or any Garda Station.