Ulster Unionist leader Mr David Trimble tonight urged Northern Secretary Dr John Reid to take action against the IRA.
The two men refused to comment after an hour-long meeting in London but sources close to Mr Trimble said he had pressed Dr Reid on the status of the IRA ceasefire.
"He specifically pressed Dr Reid to define what he regards as a ceasefire . . . He wanted to know if it was okay to train terrorists in Colombia so long as police and soldiers are not getting shot in Northern Ireland," the source said.
A Northern Ireland spokeswoman described the meeting as a "useful exchange".
She said: "The Secretary of State listened to Mr Trimble's views on the seriousness of the situation."
A political crisis is looming with the IRA being accused of training FARC guerillas in Colombia, stealing intelligence files during a raid on Special Branch offices in Belfast and compiling a hit-list of senior Conservatives.
Under pressure from hardline elements in his party to impose sanctions against Sinn Fein ministers in the power-sharing Executive, Mr Trimble has said it is up to Dr Reid to take the initiative to save the process.
Yesterday he warned that if Dr Reid failed to act, unionists would be left with the "nuclear option" of bringing down the Belfast Agreement.
PA