Two men have been arrested in south Belfast in connection with the attempted murder of an unarmed police officer in London earlier this month.
The men, aged 20 and 26, were held after the search of a house on the Lisburn Road on Wednesday night.
The property was searched and a number of items were taken away for examination.
Detectives from the Metropolitan Police travelled to Northern Ireland to bring back the 26-year-old suspect to London for questioning.
According to the Metropolitan Police, officers from Operation Trident, which investigates gun crime among the black community, worked alongside PSNI officers to find the men but could not confirm where the intelligence regarding the arrests had come from.
A 20-year-old man arrested is being held in custody by officers from the PSNI for questioning in relation to assisting offenders.
The two men were arrested on Wednesday evening in connection with the shooting of a police officer in south Croydon on July 15 after he attended a call-out.
A spokesman for the Metropolitan Police said officers were called after a group of men were seen acting suspiciously but ran off as officers arrived.
Police chased the group who made off on foot and one suspect produced a handgun firing several shots, striking one male officer on the arm.
Two men, aged 21 and 22 were arrested at the scene and have since appeared in court.
Adewale Ogunsanya (22) from Leigham Court Road, London, and Demar Provan (21), of no fixed address, appeared at Croydon Magistrates' Court on July 18 charged with possession of a firearm with intent to endanger life and possession of ammunition and are now due to appear before Croydon Crown Court on September 23.
A third man, aged 18, was released on bail and is to appear in court in early September.
Councillor Bob Stoker said he was concerned Belfast could now be used as a "bolt-hole" for criminals from outside the region.
"I would question the security at the border - if they were aware who they were looking for, then there's questions to be asked," he said. "How someone from London hiding their activities can do it so easily, although it seems they have been apprehended very quickly, so there has been good co-operation between police here and in England."
Police also carried out a search of a house in the Ravenhill Avenue area of the city as part of the ongoing investigation.