UPDATE 1-UK postal workers suspend strike action

* Strikes halted until after Christmas

* Definitive agreement still to be reached

(Adds quotes, reaction)

LONDON, Nov 5 (Reuters) - British postal workers said on Thursday they would suspend strike action until at least after Christmas under an interim agreement reached between unions and state-owned Royal Mail.

Brendan Barber, head of union umbrella group the TUC, told reporters that no definitive agreement had been reached to resolve a long-running row over jobs, pay and modernisation.

However, he said strike action had been suspended pending further efforts to settle the dispute and to prevent disruption of deliveries at the busiest time of the year.

"The agreement provides for a period of calm, free of industrial action, to enable negotiations to be held over the next couple of months through to the end of the year to secure the longer-term agreements necessary on all aspects of modernisation of Royal Mail," Barber said.

"The delivery of the terms of this agreement means that Royal Mail services will be free of any disruption up to and through the Christmas period," he said.

A third wave of national strikes was due to have taken place on Friday and Monday.

Business Secretary Peter Mandelson welcomed the news.

"I hope very much indeed that we will not see further strikes," he told reporters.

"I hope very much indeed that if there are issues that have got to be resolved, if there are wrinkles in the modernisation process -- which is absolutely vital for Royal Mail -- that these wrinkles will be smoothed out by discussion and negotiation without resorting to further strikes in the future." (Reporting by Stefano Ambrogi and Adrian Croft; Editing by Keith Weir)