An IRS spokesman told The Wall Street Journal that as many as 362,000 Americans fall under the category of those with outstanding debt for whom the State Department should deny passport applications or renewals.

The State Department confirmed separately to the Journal that some passports had already been denied under the enforcement, as the IRS sends the names of those with outstanding debt in batches to the agency.

For now, agency officials stressed that they are just denying applications for new or renewed passports, and were not revoking passports from any Americans with outstanding debt.

The new law's effects are already noticeable, according to an IRS spokesman, who told the Journal that 220 people had handed over $11.5 million to repay their full debts as of late June, while 1,400 others had set up payment plans to reduce their debts.