FILE PHOTO: The U.S. Capitol is shown after the U.S. government reopened after a 35-day shutdown in Washington, U.S., January 28, 2019. REUTERS/Joshua Roberts

WASHINGTON (Reuters) - The partial U.S. government shutdown in December and January caused “real harm” to taxpayers, with many unable to get help from officials to understand their tax obligations, a government watchdog said.

In a report released on Tuesday, the Internal Revenue Service watchdog said the 35-day shutdown cut back on the number of IRS call center agents who were able to talk to taxpayers about preparing their returns.

“Make no mistake about it, these numbers translate into real harm to real taxpayers,” the National Taxpayer Advocate, an internal IRS watchdog, said in a report to Congress.

The shutdown, which was the longest in U.S. history, also added to backlogs piling up for IRS workers, leaving them unable to ship tax forms to businesses in time this year for companies to meet some filing deadlines, according to the report.

“The IRS therefore suggested that employers consider requesting filing extensions,” according to the report, which also called on Congress to budget more funding for tax collectors.

The shutdown came after an impasse between congressional Democrats and Republicans over President Donald Trump’s request to build new physical barriers on the U.S. southern border with Mexico.

Lawmakers hammered out a deal on Monday night to avoid another shutdown that will begin on Saturday unless new spending legislation is passed. But Trump said he has not decided whether to support the agreement.