Anti-Agreement unionists have said the discovery of a major arms find in south Belfast shows the Provisional IRA is still wedded to violence and makes a new political deal in the North more unlikely.
Three men are being questioned by detectives after the weapons find in the lower Ormeau Road. Six handguns, an assault rifle, timer power units and 2,000 rounds of ammunition were among the items seized during the raid on a house in Essex Street on Saturday night.
The PSNI said it was confident the arms belonged to the Provisional IRA. Supt Ken Dean described the find as "very significant".
"What we have is a mixture of firearms, ammunition and bomb-making equipment and components," he said. "At this stage, we have reason to believe this is mainstream Provisional IRA equipment and the find is being attributed to that organisation."
Ulster Unionist MP, Mr Jeffrey Donaldson, said the arms discovery showed Sinn Féin was unfit for government and there must be total Provisional IRA disarmament.
"These weapons were not found in an arms dump in a remote rural area. This was a forward arms cache in a built-up residential district. These weapons were obviously ready for use.
"The presence of these weapons in such a location, combined with evidence of the targeting of individuals by the Belfast Brigade in recent months, raises serious questions about the intentions of mainstream republicans.
"This find is a body blow to the peace process at a very crucial time."
DUP MP, Mr Nigel Dodds, said the arms discovery showed British government demilitarisation plans were "scandalously premature while the Provisional IRA clearly remained active".