The move follows an evaluation in Washington of Mr Adams's trip earlier this month - which is now seen increasingly by the Clinton Administration as having handed Mr Adams a propaganda coup with little in the way of positive results for the peace process.
The move comes amid signs that President Bill Clinton is seeking to make a big effort during John Major's trip to the US next week to demonstrate that the Anglo-US relationship has not been ruptured by recent differences over Bosnia and the granting of the initial application by Mr Adams.
Mr Major will impress on Mr Clinton when they meet on Monday and Tuesday the Government's strong view that a further US trip by Mr Adams at present would be unwelcome and merely give him a second publicity platform.
The signs are that he will get a sympathetic hearing. US sources pointed to Mr Clinton's refusal 'to be drawn into the IRA's web' during Mr Adams's trip and his unequivocal public declaration of support before Mr Adams left New York for the Anglo-Irish Downing Street declaration.
Mr Adams has been invited to take part in the San Francisco St Patrick's Day parade but has apparently not yet sought a second waiver of the US exclusion order.
Sinn Fein said yesterday that a 'definitive' response to the Downing Street declaration was unlikely to emerge from the party's annual conference in Dublin this weekend. An emergency motion tabled by the executive of the IRA's political wing for the two-day meeting merely repeats demands for clarification from Britain.
Pat McGeown, a Sinn Fein official, said: 'There are issues needing to be clarified. As soon as we get clarification we will respond.'
About 400 delegates are expected at the conference.
A surveillance operation which led to the arrest of two IRA suspects in London and Lancashire probably prevented a bombing campaign and is evidence of improved intelligence gathering, sources said last night.
The two men are being questioned at the high-security Paddington Green police station in London after being arrested during a joint operation involving MI5, Special Branch and the Metropolitan Police Anti-Terrorist Branch.
One man was arrested in Accrington, Lancashire, on Monday night after armed police, in a carefully planned operation, stopped his car and discovered explosives, bomb-making equipment, a firearm and ammunition. Police surrounded the Rover car next to a tyre and exhaust centre in Accrington.
One eye-witness said: 'An unmarked car pulled up outside and police in plain clothes started pulling flak jackets on and taking semi- automatic weapons out of the back. The next thing there were armed police everywhere. They went round the side and the next thing I saw they had a man pinned on the floor with his arms taped behind his back.'
Shortly afterwards a second man was arrested in north London under the Prevention of Terrorism Act. The suspect seized in Accrington was later taken to the capital.
These are the latest in a series of arrests of terrorist suspects in England over the past 18 months. While some have been the result of luck, others have shown that intelligence on IRA units operating on the British mainland has improved.
It is thought that there may be only 30 to 40 terrorists and active helpers operating on this side of the Irish Sea. Responsibility for co-ordinating the fight against the IRA has been moved from Special Branch to MI5.
A terrace house in Accrington, which police confirmed was connected with the arrest, was being guarded by officers last night.
An unexploded firebomb was found in a shop in Edgware Road, central London, yesterday, two days after similar devices damaged several stores in the capital. Police defused it.