Sen. Rand Paul (R-KY) wrote Friday that he had sought records to determine whether he or other members of Congress had been surveilled by the Obama administration or by the intelligence community.

The announcement came after a series of tweets on surveillance:

Did the Obama admin go after presidential candidates, members of Congress, journalists, clergy, lawyers, fed judges? https://t.co/h7rsjvNLHM — Senator Rand Paul (@RandPaul) May 5, 2017

Did the Obama admin use warrantless "wiretapping" on other candidates besides @realDonaldTrump? https://t.co/h7rsjvNLHM — Senator Rand Paul (@RandPaul) May 5, 2017

I have formally requested from the WH and the Intel Committees info on whether I was surveilled by Obama admin and or the Intel community! — Senator Rand Paul (@RandPaul) May 5, 2017

Paul’s press office did not respond to TPM’s questions about what prompted the tweet, but the news website Circa reported a couple hours later that Paul had written to the White House on April 10 claiming that “an anonymous source recently alleged to me that my name, as well as the names of other Members of Congress, were unmasked, queried or both, in intelligence reports of intercepts during the prior administration.” In a press release obtained by TPM, Paul cited Circa’s reporting and attached his letter to Trump.

Two of Paul’s tweets link to a call from Circa for the Trump administration to release “records showing how often government officials have searched National Security Agency intercepts for intelligence on U.S. presidential candidates, members of Congress, journalists, clergy, lawyers, federal judges and doctors and how often such Americans had their identities unmasked by the intelligence community after Barack Obama made it easier to do so in 2011.”

The publication doesn’t make clear what changes occurred in 2011, but another report from the publication linked in the same article describes “a series of orders that began in 2011, moves that were approved by the [Foreign Intelligence Surveillance Court].”

Circa reported, based on unnamed intelligence officials and classified documents, it said, an increase in 2016 in U.S. names searched for and unmasked in intercepted communications, among other things. Among names unmasked in 2016 and early 2017, it reported, “were campaign or transition associates of President Trump as well as members of Congress and their staffers, according to sources with direct knowledge.”

In the final days of his administration, Obama announced new rules broadening the NSA’s authority to share large amounts of collected data with other agencies.

The senator, a proponent of privacy protections against government surveillance, has played sympathetic to President Donald Trump’s unsubstantiated claim in February that Trump Tower had been wiretapped on former President Obama’s order.

Trump has since dramatically expanded his accusation to include “unmasking” by the Obama administration of his or his associates’ names in communications, which would include their names being unveiled as part of separate conversations.

In April, Paul said, referring to the former national security adviser, “I believe Susan Rice abused the system and she did it for political purposes. She needs to be brought in and questioned under oath.” He added: “This was a witch hunt that began with the Obama administration, sour grapes on the way out the door. They were going to use the intelligence apparatus to attack Trump, and I think they did.”

House Intelligence Committee Chair Devin Nunes (R-CA) said in March that he had seen proof of that unmasking after secretly meeting with a source he called a “whistleblower” a the White House. The ranking member on that committee, and lawmakers from both sides of the aisle, said the documents showed no evidence of improper surveillance.

Nunes subsequently stepped aside from the committee’s probe of possible connections between Russia and the Trump campaign.

Read Paul’s Apr. 10 letter to Trump below: