(NewsNation) — The chairman of the committee investigating the Afghanistan withdrawal will pursue holding Secretary of State Antony Blinken in contempt of Congress, a source close to the investigation tells NewsNation.

House Republicans delivered a subpoena in March to Blinken for classified cables related to the chaotic withdrawal.

Last week, Rep. Michael McCaul, R-Texas, and chairman of the House Foreign Affairs Committee, sent a letter to Blinken, threatening to hold him in contempt of Congress or initiate a civil enforcement process should he not follow the subpoena.

McCaul said in a statement to NewsNation Friday that the group has been “more than reasonable” in providing Blinken time to comply.

“If the department fails to do so, I am prepared to initiate contempt proceedings,” he said. “This is not a decision I take lightly, but Congress and the American people, particularly our veterans and Gold Star Families, deserve answers on this catastrophic withdrawal.”

A State Department spokesperson told the Associated Press, which also reported on the threat to hold Blinken in contempt, that it is “unfortunate” that despite the House Foreign Affairs Committee having received a classified briefing on the dissent cable and a written summary it “continues to pursue this unnecessary and unproductive action.”

The department would nevertheless “continue to respond to appropriate oversight inquiries and provide Congress the information it needs to do its job while protecting the ability of State Department employees to do theirs,” principal deputy spokesperson Vedant Patel said in a statement.

The Associated Press contributed to this report.