BP says it has received a demand from U.S. authorities for advance notice of any asset sales or significant cash transfers.

It donfirmed a report in the Financial Times on Wednesday that U.S. assistant attorney general Tony West wrote to the company on June 23. Normally the U.S. Justice Department does not require advance notice of such deals.

BP spokeswoman Sheila Williams said the oil company had not responded to the letter but would do so “in due course.” She declined to say whether the Justice Department had set a deadline.

The letter underlines the U.S. government’s intense scrutiny of BP as it struggles to cap the oil leak in the Gulf of Mexico and clean up the damage.