Royal Bank of Scotland announced thousands of new job cuts on Thursday as the part-nationalised bank continues with its drive to trim costs and improve its profitability.

RBS, which is 83 percent owned by the British taxpayer, said it was cutting 3,500 jobs in administration centres across the country.

Trade unions attacked the move, which RBS said formed part of its plans to repay its bailout from the taxpayer and make its business more efficient.

The news that the Royal Bank of Scotland is to cut another 3,500 staff from across the UK is a horror story, Rob MacGregor, national officer at the Unite trade union, said in a statement.

Financial companies around the world have slashed thousands of jobs in the wake of the global credit crisis; in July, U..S. bank Wells Fargo announced 3,800 job cuts, and Bank of Ireland said it would axe 750 jobs, while earlier this week UK insurer Standard Life said 500 jobs would go.

Since 2009, RBS has shed more than 20,000 jobs. The latest cuts come on top of a decision in May to shed 2,600 posts at RBS's insurance and British retail banking operations.

RBS currently employs 160,000 staff globally, most of them in the UK.

The job cuts come as RBS looks to restructure its business after European regulators ordered it to sell a string of assets as a price for its state bailout.

RBS had to be rescued by the British government in October 2008 after its finances were stretched by the credit crisis and its part in the acquisition of Dutch bank ABN AMRO in 2007.

The bank was propped up with 20 billion pounds of taxpayers' money, causing the eventual resignation of then chief executive Sir Fred Goodwin, who helped preside over an aggressive acquisition policy that included the 2000 takeover of NatWest.

RBS shares were up 0.7 percent at 46.12 pence at 1135 GMT, outperforming a flat FTSE 100 index .FTSE and a 0.2 percent fall in the STOXX Europe 600 banks index .SX7P. (Editing by David Holmes and Will Waterman)