Postal workers at Britain's Royal Mail will strike for six days in the run-up to the busy Christmas period in a dispute over pay and conditions, their union said on Thursday.

The workers will strike on Dec. 23 and 24, in addition to Dec. 9, 11, 14 and 15, the Communication Workers Union (CWU), which represents more than 115,000 postal workers at Royal Mail, said in a statement.

The strikes are in addition to walkouts scheduled for three days later this month and on Dec. 1.

“The CWU want a negotiated settlement with Royal Mail Group and will continue to engage the company to that end," a union spokesperson said. "But those in charge of Royal Mail need to wake up and realise we won’t allow them to destroy the livelihoods of postal workers."

News of the walkout comes a day after Royal Mail, the British arm of International Distribution Services, said

talks with the union

aimed at averting a strike had been extended.

“Our preference is for an agreement with the CWU, but the change we need is not optional," a Royal Mail spokesperson said. "They should be focussed on a resolution to this dispute for their members and the long-term health of the business, rather than damaging strike action.” (Reporting by Sachin Ravikumar; Additional reporting by Sneha Bhowmik in Bengaluru; Editing by Jonathan Oatis, Nick Macfie and Deepa Babington)