By Jeremy Diamond

CNN

WASHINGTON (CNN) -- The President's tax returns and White House visitor logs -- both public information under the previous administration -- will remain private under President Donald Trump.

White House press secretary Sean Spicer on Monday dealt another blow to transparency advocates, announcing that Trump's 2016 tax returns are under audit and therefore would not be released, and defended the White House's decision to reverse an Obama administration initiative and make White House visitor logs private.

"They are," Spicer said of the 2016 tax returns being under audit.

Moments later, he added: "We're under the same audit that existed, and so nothing has changed."

Mandatory audit

And per federal law, the President and vice president's taxes are audited annually.

The practice of doing a "mandatory examination" of the presidential and vice presidential tax returns has been in the Internal Revenue Manual since the Watergate era, according to the IRS.

Both President Richard Nixon and Vice President Spiro Agnew became embroiled in personal tax controversies around the same time that the Watergate scandal was unfolding. Agnew ended up resigning after admitting to tax evasion.

Trump has refused to release his tax returns, breaking with decades of precedent by arguing that he would not release them while those returns are under audit, though there is nothing legally preventing him from doing so.

Pressed whether Trump was prepared to rule out ever releasing his tax returns, Spicer demurred: "I'll have to get back to you on that."

Spicer's comment about Trump's 2016 tax returns came a day before the federal tax filing deadline and followed a weekend of protests in cities across the country where protesters demanded Trump release his tax returns. Trump, though, has typically been granted an extension until the following October to file his taxes due to their complex nature.

Visitor logs

Spicer also defended the administration's decision, announced last Friday, to make White House visitor logs private.

The logs -- which record the comings and goings of visitors, including lobbyists, at the White House -- were publicly disclosed under the Obama administration.

Spicer insisted that the administration was simply "following the same policy that every administration from the beginning of time has used."

Spicer said there is also a "privacy aspect" concerning the visits and that visitors should be able to come to the White House to express an opinion without their visit becoming public.

He also knocked the Obama administration's decision to publicize the visitor logs, which left off some visitors due to national security concerns, arguing that they could keep some people off the visitor log list "for whatever reason."

The decision to keep the visitor logs private, though, struck critics as hypocritical in light of Trump's pledge to "drain the swamp," ridding Washington of the influence of special interest groups and lobbyists, which Trump railed against during his campaign.

"This is the policy that's existed from the beginning of time since they were kept," Spicer said in response to the criticism.

CNNs Jeanne Sahadi contributed to this report.