WASHINGTON (AP) — The U.S. State Department will begin revoking the U.S. passports of thousands of parents who owe a significant amount of unpaid child support.

The department told The Associated Press on Thursday that the revocations would begin Friday and be focused on those who owe $100,000 or more. That would apply to about 2,700 American passport holders, according to figures supplied to the State Department by the Department of Health and Human Services.

The revocation program, plans for which were first reported by the AP in February, soon will be greatly expanded to cover parents who owe more than $2,500 in unpaid child support — the threshold set by a little-enforced 1996 law, the State Department said.

It was not clear on Thursday how many passport holders owe more than $2,500 because HHS is still collecting data from state agencies that track the figures, but it could encompass many more thousands of people, officials said.

Until this week, only those who applied to renew their passports were subject to the penalty. Under the new policy, HHS will inform the State Department of all past-due payments of more than $2,500 and parents in that group with passports will have their documents revoked, the department said.

“We are expanding a commonsense practice that has been proven effective at getting those who owe child support to pay their debt,” Assistant Secretary of State for Consular Affairs Mora Namdar said. “Once these parents resolve their debts, they can once again enjoy the privilege of a U.S. passport.”

Since the AP reported the expansion of the program on Feb. 10, the department said it had “seen data that hundreds of parents took action and resolved their arrears with state authorities since news broke that the State Department would start proactively revoking passports.”

“While we can’t confirm the causation in all of those cases, we are taking this action precisely to impel these parents to do the right thing by their children and by U.S. law,” the department said.

Even before the policy was expanded, the department said the program had been a “powerful tool” to get parents to pay what they owed. It said that since it began in earnest in 1998, states had collected some $657 million in arrears, including more than $156 million in over 24,000 individual lump-sum payments over the past five years.

Those whose passports are revoked under the program will be notified that they will not be able to use their documents for travel and will have to apply for a new passport once their arrears are confirmed as paid.

A passport holder who is abroad at the time of revocation will need to visit a U.S. embassy or consulate to obtain an emergency travel document that allows them to return to the United States.