As Wal-Mart reported higher-than-expected first-quarter earnings on Thursday, it suggested in a regulatory filing that the scope of an internal investigation into bribery accusations had widened beyond the retailer’s subsidiary in Mexico.


The company reported that the audit committee of the Wal-Mart Stores board was examining possible violations of the Foreign Corrupt Practices Act and “other alleged crimes or misconduct in connection with foreign subsidiaries, including Wal-Mart de México.” It was the first public disclosure by the company that the internal inquiry could involve additional subsidiaries, though none was named.


The regulatory filing also confirmed that Wal-Mart is the subject of investigations by the Securities and Exchange Commission and the Justice Department. And while Wal-Mart said in December that it did not expect the bribery accusations and their fallout to hurt the company, it backed away from that assertion on Thursday.


“Although the company does not presently believe that these matters will have a material adverse effect on its business, given the inherent uncertainties in such situations, the company can provide no assurance that these matters will not be material to its business in the future,” the filing said.


A Wal-Mart spokesman, David Tovar, declined to comment further on the filing.


The disclosures on Thursday caught some analysts by surprise. Faye Landes, an analyst with Consumer Edge Research, wrote in a note to clients that the new information was “dramatic.”


“They can’t leave any stone unturned,” Ms. Landes said. “Now they have to make sure that everything is squeaky clean.”


The New York Times reported last month that Wal-Mart had found credible evidence that its Mexican subsidiary had paid bribes and that an internal inquiry into the matter had been suppressed at corporate headquarters in Arkansas.


Also on Thursday, two congressmen who are looking into Wal-Mart’s activities in Mexico said they had internal company documents that showed the company’s former general counsel had pushed for an investigation of some transactions in Mexico before she resigned in 2006.


Representatives Elijah E. Cummings and Henry A. Waxman reiterated a request that Wal-Mart brief them on the bribery accusations, and asked that Wal-Mart authorize the former general counsel to speak to them. Mr. Tovar said Wal-Mart had already scheduled an initial briefing with the congressmen’s staffs, and was working to schedule another session.


Egan-Jones Proxy Services, which advises institutional investors, recommended on Thursday that shareholders vote against re-electing Wal-Mart’s chief executive, Michael T. Duke, and a board member, H. Lee Scott Jr., in June because of accusations that they were involved in the bribery case.


In a call with investors, Mr. Duke said, “We are working aggressively to determine what happened, and we will take appropriate action if violations of the law or our policies occurred.” Asked in a call with reporters to give an update on the timeline of the investigation or expectations about June’s shareholder meeting, Mr. Tovar, the Wal-Mart spokesman, declined to comment.


Wal-Mart also warned in Thursday’s filing that its reputation could be affected by the bribery scandal, with inquiries from the media and law enforcement authorities affecting the “perception among certain audiences of its role as a corporate citizen.”


Possible outcomes include enforcement actions that could lead to fines or criminal convictions; judgments against the company from shareholder lawsuits; and costs from the government’s investigations, from its own investigation and from defending itself against the lawsuits, the filing said.


The company “cannot predict at this time the ultimate amount of all such costs.” Further, the inquiry could involve some senior executives, and that could “could impinge on the time they have available to devote to other matters relating to the business.”