Police are continuing to question a 54-year-old man arrested in connection to a number of security alerts in Belfast.
The man was arrested by police on suspicion of a number of offences, including possessing and making explosives in suspicious circumstances and intimidation, following a search of a house in the Braniel area of east Belfast on Thursday night.
It is part of an ongoing investigation into a series of incidents, including alerts at Mayfield Square in west Belfast and Dundela Road in east Belfast.
They are being linked by police to a security incident on Wednesday at the Henry Jones playing fields where members of East Belfast GAA had been training.
Police were alerted to the incident following a telephone warning that devices had been left in the area.
Three cars, two in east Belfast and one in west Belfast, and three items that had been placed on them, have been recovered for further forensic analysis.
Chief Superintendent Jonathan Roberts said: “We believe these incidents, which are being treated as sectarian hate crimes, are linked.
“I would also ask anyone who was in the area at the time who saw anyone acting suspiciously, or anyone with information which could help our investigation, to contact police on 101.”
In a statement issued earlier this week, a spokesman for East Belfast GAA said: “The creation and maintenance of a safe environment for sport to be played by all and the safety of our members whilst playing remains a priority for us all.
“The club intends to continue to work with the police, the community in East Belfast, and the public at large, whose support we have enjoyed on a daily basis, to ensure the continued safety and enjoyment of our members and patrons.
“Our door remains open, to all.”