(Adds DOJ investigation)
RIO DE JANEIRO, Nov 24 (Reuters) - Brazil's state-run oil firm Petroleo Brasileiro SA said on Monday it had received a subpoena from the U.S. Securities and Exchange Commission asking for documents relating to an investigation it is pursuing.
The SEC investigation is the latest in a multi-layered probe into Petrobras which is spreading beyond Brazil's borders.
Petrobras, as the firm is known, said the requested material would be sent to the SEC and it was working with law firms Trench, Rossi and Watanabe, and Gibson, Dunn & Crutcher, which have already been hired to lead an internal investigation into allegations of corruption at the company.
Petrobras did not provide details as to what documents the SEC had requested.
The company is also under investigation by the U.S. Department of Justice, according to a person familiar with the matter who was not authorized to speak publicly about the matter.
A DOJ spokesman declined to comment.
The oil producer's activities are being probed by a DOJ unit that looks into potential violations of the U.S. Foreign Corrupt Practices Act, the person said.
The U.S. investigation, conducted by both the SEC and the DOJ, is "broad" in nature and has been ongoing since at least the start of 2014, the person said.
In Brazil federal police have already arrested two former senior Petrobras executives in a wide money-laundering and bribery probe, while an internal investigation at the firm has led to one employee being fired and 15 others fingered for corruption.
Prosecutors allege Petrobras systematically overpaid for work by contractors and that the excess funds were then illegally funneled to political parties, including that of President Dilma Rousseff.
The scandal has put pressure on Rousseff after her narrow re-election last month, particularly because she was chairwoman of the Petrobras board from 2003 to 2010, when much of the alleged corruption took place.
Petrobras said it would cooperate with American authorities to the same extent as it has with Brazilian authorities. (Reporting by Stephen Eisenhammer; additional reporting by Aruna Viswanatha in Washington D.C; Editing by Chris Reese and Richard Chang)