The Continuity IRA is being linked to a raid in the premises of a gun dealer in the border village of Garrison, County Fermanagh, on Saturday night.
Three masked men carried out the raid, taking nine handguns, including two 9mm pistols and a .22-caliber gun.
A getaway vehicle was found burnt out later in the nearby village of Belleek.
The organisation has carried out a number of attacks on the PSNI police in the border areas of the county over the past year, and is increasingly active in Belfast.
Meanwhile, a statement by the group to a Belfast newsroom claimed to have shut down a drugs factory in West Belfast last weekend and also threatened drug-dealers.
The statement reads: “Members of the CIRA in Belfast successfully closed down a drugs factory in West Belfast. On Saturday the 15th November volunteers of the CIRA went into a workshop in the West of the city and destroyed a large number of cannabis plants.
“The CIRA would like to inform all drug dealers in the Belfast area that this is just the start of what is an ongoing campaign and anyone found dealing drugs will be dealt with severely.”
The statement is signed the ‘CIRA Belfast Leadership’ and also includes photographs of a man standing beside the the cannabis plants and cultivation equipment brandishing a handgun.
In another statement, the CIRA also warned Catholics to cease working in community outreach schemes involving the PSNI or be considered ‘legitimate targets’.
The threat singled out workers from the Ashton Centre in the New Lodge and the Wolfhill Community Centre in Ligoniel, both in North Belfast.
The PSNI have been increasingly involved in the activities of the groups, which employ more than a hundred staff, with dozens of young people and pensioners taking part in a range of activities in the centres every day.
Extra security measures have been introduced at the centres.
The Continuity IRA statement said: “These groups such as the Ashton Centre and Wolfhill Centre are not only putting themselves at risk but also their staff.”
Claiming that the threat was in response to PSNI harassment of republicans, it said: “There will be no second warning, this threat will only be lifted when the harassment of innocent civilians stops.”
In July the Continuity IRA threatened to kill Customs and Revenue staff and workers at the North’s Vehicle Licensing Authority, after accusing them of collaborating with the PSNI.
SInn Féin Assembly member Gerry Kelly criticised the threat to community groups.
“Literally every community group in North Belfast is under threat. These people cannot accept progress. They are threatening children and pensioners. They have no support and no political direction.”
A PSNI vehicle was attacked during a bomb alert in County Armagh on Sunday.
British Army bomb-disposal experts were called to the Cornakinnegar Road area of Lurgan after a suspicious object was discovered.
The area which backs on to the nationalist Kilwilkie estate was sealed off for much of Sunday afternoon.
A PSNI spokeswoman said that while attending the alert, the force came under attack from a crowd throwing petrol bombs, stones, fireworks and other missiles.
She said one of their vehicles was “extensively damaged” during the incident, but that there were no injuries.
A number of controlled explosions were carried out before the alert was declared a hoax.
Meanwhile, a device described as “viable” caused an alert that lasted five hours at a commercial premises in south Belfast on Tuesday.
The PSNI denied reports that it had maintained a news blackout on the incident over fears that it might damage city centre trade in the lead up to Christmas.