Sepp Blatter has stated he will remain as Fifa president despite the opening of criminal proceedings against him because he “has done nothing wrong or improper”, according to a statement from his lawyer.

Blatter also insisted the £1.3million payment to Uefa president Michel Platini for work done more than nine years previously was legitimate.

Both Blatter and Platini are being investigated by Fifa’s ethics committee following the opening of the proceedings against the Fifa president.

A statement from Blatter’s lawyer said: “President Blatter spoke to Fifa staff today and informed the staff that he was cooperating with the authorities, reiterated that he had done nothing illegal or improper and stated that he would remain as president of Fifa.”

The proceedings against Blatter were opened by the Swiss attorney general on Friday and concerned TV rights deals sold to the now-disgraced former vice-president Jack Warner and the payment to Platini.

The statement added: “On the Platini matter, President Blatter on Friday shared with the Swiss authorities the fact that Mr Platini had a valuable employment relationship with Fifa serving as an advisor to the president beginning in 1998.

“He explained to the prosecutors that the payments were valid compensation and nothing more and were properly accounted for within Fifa including the withholding of Social Security contributions.

“Because of the continuing investigation President Blatter will answer no further questions at this time.”

Platini also released a letter he has sent to the 54 UEFA associations insisting the payment had been above board and declared to the Swiss authorities – but he did not address the burning issue of why it had taken nine years for the money to be paid to him.

The Frenchman, who had been the favourite to succeed Blatter in February’s election, did admit that the controversy may damage his reputation.

He said: “I’m aware these events may harm my image and reputation... and I wish to use all energies to ensure that any issues or misunderstandings can be resolved as soon as possible.”

Platini also disclosed he has written to FIFA’s ethics committee asking that he can clarify the payment with them.