A group of National Guard soldiers who were ordered to protect possible targets after the Sept. 11 attacks sued the federal government Wednesday, seeking tens of millions of dollars in expenses they say were never reimbursed.

The soldiers, from Massachusetts and New Hampshire, say they traveled hundreds of miles to security postings and used their own money to pay for food and lodging with the expectation that they would be reimbursed.

But the soldiers say in their complaint that their requests for compensation were repeatedly denied and they eventually were told, "If you don't like the arrangement, we'll make sure you get taken off this mission."

In the lawsuit, the plaintiffs argue that federal law provides military personnel with a travel and transportation allowance while away from home on active duty.

The lawsuit was filed in U.S. District Court by four soldiers but seeks to include hundreds of other guardsmen as a class action. It names the U.S. Department of Defense and the Massachusetts National Guard and seeks $73 million in unpaid expenses.

A spokeswoman for the Pentagon referred all calls to the Department of Justice, where a spokesman did not immediately respond to a message seeking comment.

A call to a Massachusetts National Guard spokesman was not immediately returned.

The plaintiffs are Steven Littlefield of Plymouth, Wayne Gutierrez of New Bedford, Louis Tortorella of Brookline, N.H.; and Joseph Murphy of Derry, N.H. All but Tortorella are still in the National Guard. The areas they patrolled included Boston's primary water supply.