London, England (CNN) -- Some 35 million pieces of mail have been delayed by this week's British postal strikes, Royal Mail said Friday.
Thousands of postal staff have walked off the job in three days of strikes this week in a dispute over modernization plans, job security, and workloads. It follows two consecutive days of nationwide strikes last week that resulted in limited collection and delivery of mail.
Royal Mail said it had cleared "virtually all delays" caused by last week's strikes and was working to clear delays caused by the work stoppage this week.
More than 43,000 postal staff across the United Kingdom went on strike Thursday at mail centers and distribution units, according to Royal Mail and the Communication Workers Union, which represents the striking workers.
Some 400 people in three cities in England went on strike Friday, and 77,000 delivery and collection staff, including postmen, were due to strike Saturday, the union said.
The two sides came together for talks Thursday night and again on Friday to seek a resolution, according to a spokesman at the Trades Union Congress, which is mediating the dispute.
"Further work is needed on all sides to finalize the terms of a possible settlement, and I have put a number of proposals to Royal Mail and the CWU to consider on possible approaches to some of the big issues that remain in dispute," said TUC general secretary Brendan Barber.
"They have agreed to look at these proposals over the weekend and consult appropriately with colleagues with a view to returning to the TUC for further negotiations early next week."
Union members have complained that Royal Mail has not consulted the union on its plans to bring in changes such as new machines that might replace certain positions and lead to layoffs. They are also unhappy that Royal Mail hired thousands of temporary workers ahead of the strikes.
The walkouts have caused concern among businesses and retailers, especially those who rely heavily on direct mail, that the effects could last through Christmas.