Rolls-Royce has said that it is handing over the findings of a review to the Serious Fraud Office over allegations of bribery and corruption.
The company said it had followed a request from the SFO over possible misdealings in Indonesia and China.
"I want to make it crystal clear that neither I nor the board will tolerate improper business conduct of any sort and will take all necessary action to ensure compliance," said chief executive John Rishton said in a statement.
"This is a company with exceptional prospects, and I will not accept any behaviour that undermines its future success."
Shares in the company fell 5 per cent at the start of trading.