WASHINGTON_Wal-Mart has embraced President Barack Obama's call for requiring all large employers to offer health insurance to their workers.

The move, joined by a major labor union, could add momentum to Obama's push for far-reaching changes to the nation's health care system, which Congress is weighing.

Wal-Mart, the nation's largest private employer, announced its position in a letter to congressional and administration officials Tuesday.

The letter said that the company is for "an employer mandate which is fair and broad in its coverage."

The letter was also signed by the president of the Service Employees International Union, which has more than a million members.