WASHINGTON — The Senate moved Tuesday to impose new restrictions on the closing of rural post offices, adopting a provision that would prevent them from being shuttered for at least a year.

Under the measure, the ailing Postal Service would be barred from closing post offices for one year if they are located in rural areas — those with fewer than 50,000 people. The exception would be if there was no community opposition.

After one year, the mail agency would have to take rural issues into special consideration, including economic impact, the quality of Internet broadband service and location. Post offices would generally be shielded from closing if the next closest mail facility was more than 10 miles away.

The provision was among revisions to a Senate bill aimed at stabilizing the ailing U.S. Postal Service by providing a short-term cash infusion while delaying controversial decisions on thousands of post office closings and ending Saturday mail delivery.

Senators were scheduled to vote on a final measure as early as today.

“Protecting our rural post offices is about more than just maintaining brick and mortar — our post offices are the lifeblood for towns across our state and a source of good-paying jobs in areas hard-hit by the economic downturn,” said Claire McCaskill, D-Mo., who co-sponsored the amendment, which was agreed to by voice vote.”

The mail agency, teetering on the brink of bankruptcy, says it needs to begin closing thousands of low-revenue post offices and mail-processing centers this year as part of a billion-dollar cost-cutting effort to become profitable again by 2015. Postmaster General Patrick Donahoe previously agreed to delay post office closings until May 15 to allow Congress to pass legislation.