WASHINGTON BUREAU — American International Group (AIG) Inc. Chairman Steve Miller will become the company’s interim president and chief executive officer (CEO) if AIG CEO Robert Benmosche steps down because of illness, the AIG board says.

AIG, New York, earlier this week announced that Benmosche, 66, is undergoing aggressive chemotherapy for cancer and that the company was preparing for alternatives if he had to limit his work.

Benmosche said earlier that he feels fine and is working a full schedule.

“Bob feels fine, continues to work a normal schedule, and the board continues to assume that Bob will remain CEO on this timetable,” the board says in a new statement. “Given the effectiveness of Bob’s leadership, his commitment to his role, and the strength of the AIG management team, the board remains comfortable with its current succession planning timetable.”

Benmosche has been planning to stay at AIG until the company completes repayment of its obligations to taxpayers. AIG hopes to pay off taxpayers in 2012.

Miller, 68, would step in as interim CEO “in the event that Bob would become unwilling or unable to continue to effectively serve in his current role,” the AIG board says.

If necessary, Miller would serve as interim CEO of AIG “for as long as it takes to identify and

select a long-term replacement for Bob,” the board says.

Miller became AIG chairman in July, after Harvey Golub stepped down.

Miller oversaw the bankruptcy of auto-parts supplier Delphi Corp. and helped Chrysler Corp. return to profitability after the automaker took government loans in 1980. He has been CEO of Waste Management Inc. and Bethlehem Steel Corp.

The AIG board says it intends to review its selection criteria for the next CEO and will continue to discuss succession planning.

“The choice of a long-term successor to the CEO will include a fair evaluation of internal candidates as well as external candidates,” the board says.

The process “would then be concluded when, over the next two years, it is appropriate to name Bob’s eventual successor,” the board says.