The Royal Bank of Scotland (RBS) has set aside £2bn to cover charges of past misconduct including the PPI mis-selling scandal.

The biggest state-backed bank in the UK has reserved £1.5bn to pay for litigation claims in the US in connection to residential mortgage-backed securities. This means RBS is still dealing with 'bad debts' costs over the sub-prime mortgage crisis between 2007 and 2009.

The bank has put aside an additional £500m to cover Payment Protection Insurance (PPI) mis-selling charges. RBS was one of many financial institutions that sold PPIs to millions of customers th at did not need the insurance between 2006 and 2008.

"I am determined to put the issues of the past behind us and make sure RBS is a stronger, safer bank," said CEO Ross McEwan. We will now continue to move further and faster in 2016 to clean-up the bank and improve our core businesses.

In addition to the misconduct charges, RBS is pumping £4.2bn into its pension scheme in order to cover its £3.3bn accounting deficit. This will add an extra £1.6bn in costs, which means the total impact on the bank's book value is £3.6bn.

The total amount of charges put aside for the PPI scandal has now run up to £4.3bn, McEwan said in a conference call with the press. He also said that RBS is set to make a loss in 2015 after the charges.

The announcement comes as RBS is attempting to clear its name after years of misconduct and being bailed out by the UK government in 2008. McEwan had already pledged that the bank would dedicate its time in 2015 and 2016 to deal with legacy issues.

"We've always been open about the scale of past issues facing RBS and although there is clearly much more to do, this announcement is a further step towards addressing legacy issues and building a great bank for our customers and delivering long term value for our shareholders," he told the public.

RBS's share price was down 5% in early morning trading.