President Trump called the National Security Agency's recently announced mass-deletion of call records "a disgrace" Tuesday, and appeared to link the purge with special counsel Robert Mueller's investigation of possible campaign collusion with Russia.

The NSA said last week that it began deleting call records on May 23 from a three-year period beginning in 2015 after "technical irregularities" resulted in "the production to NSA of some [call records] that NSA was not authorized to receive."

Trump suggested there was more to the story.

"Wow! The NSA has deleted 685 million phone calls and text messages. Privacy violations? They blame technical irregularities. Such a disgrace. The Witch Hunt continues!" Trump tweeted.

Trump frequently refers to the ongoing Russia probe as a "witch hunt."

NSA spokesman Chris Augustine said "we are deferring to the White House for any comment." Charles Carithers, a spokesman for the Office of the Director of National Intelligence, also deferred to the White House.

In remarks to news outlets, NSA officials said the "irregularities" resulting in over-collection involved corporate over-sharing, and that the purge was necessary because disentangling the records would not be possible.

The NSA's power to collect domestic call records was curtailed by the 2015 USA Freedom Act, which ended the dragnet collection program revealed in 2013 by whistleblower Edward Snowden. The Freedom Act replaced the previous dragnet with a system in which companies supplied records of targets and their contacts as needed.

The NSA's privacy practices are subject to several lawsuits, some of which have active preservation of evidence orders.

Cindy Cohn, executive director of the Electronic Frontier Foundation, a group with preservation orders, said she is reviewing whether the deleted records should have been retained as part of long-running litigation, either a comprehensive surveillance challenge known as Jewel v. NSA or a call record case known as First Unitarian Church v. NSA.

Cohn said "I think it is possible" that the NSA deleted the records without notifying litigants so they would not have an opportunity to contest the deletion.

"The government is already in trouble in our case, Jewel v. NSA, for deleting information, for destroying information. They had this problem even before this latest situation and we're going to have to take a hard look at it," Cohn told the Washington Examiner.

The EFF has court orders preventing the NSA from deleting vast swaths of data, including five years worth of dragnet call record data spanning 2010 to 2015. That data must be stored in nonsearchable form, pursuant to surveillance court orders. EFF views data preservation as necessary to prove alleged violations of the Fourth Amendment.

In October, the NSA admitted that it deleted some records it had been ordered to preserve. The records included Internet communications intercepted from 2001 to 2007.

Conservative legal activist Larry Klayman, whose lawsuits against the call record program were dismissed as moot, told the Washington Examiner last week he views the deletions as an illegal cover-up.

"This is an effort to take all that evidence off the market and to protect the intelligence community, the deep state. I wasn't given notice and we have cases pending on appeal," Klayman said.

After a judge sided the with him with a major ruling in December 2013 that said NSA's call record collection likely violated the Fourth Amendment, Klayman argued unsuccessfully that his lawsuits weren't undercut by the Freedom Act. Other individuals and groups that sued were less successful, though the American Civil Liberties Union scored a federal appeals court ruling that the pre-2015 collection exceeded Patriot Act authorities.

"Obviously, they're destroying evidence," Klayman said. "It's calculated to take evidence off the market and it's obstruction of justice. The intelligence agencies continued to violate the new law. They have no respect for the law. They think they're above the law."

The Freedom Act was supposed to dramatically limit domestic call record collection, but the reforms divided privacy advocates. Many original House co-sponsors of the legislation voted against the final bill, arguing it didn't go far enough, as did Sen. Rand Paul, R-Ky.

Cohn said the NSA's admitted technical issues with call-record collection offer another reason to end the agency's domestic call record database.

"Spying on the entire country is hard. It's complicated. And it's really not possible to do it in a way that protects people's privacy," Cohn said. "And with this program in particular, there was very little indication it actually helped with terrorist investigations.... it's time for this program to go. They have been rearranging the deck chairs on the Titanic for a long time."