Defense Secretary Lloyd J. Austin III returned to the Pentagon on Monday for the first time in more than a month, the Defense Department said, after his surgery for prostate cancer and hospitalization for related medical complications.
Mr. Austin was widely criticized for failing to immediately disclose his illness and absence to the White House, a breach of protocol that baffled officials across the government, including at the Pentagon.
His return to the building came one day after three U.S. service members were killed in Jordan and at least 34 others injured in what the Biden administration said was a drone strike by an Iran-backed militia.
Mr. Austin met with the secretary general of NATO, Jens Stoltenberg, and senior defense officials, including Gen. Charles Q. Brown, the chairman of the Joint Chiefs of Staff, on Monday.
He expressed “outrage and sorrow for the death of three brave U.S. troops in Jordan, and for the other troops who were wounded” and added that “we will take all necessary action to defend the U.S. and our troops.”
Mr. Austin said he was “glad to be back at the Pentagon. I feel good and am recovering well, but still recovering.”
The House Armed Services Committee has asked Mr. Austin to testify next month about why he and his aides kept his illness secret. The committee’s chairman, Representative Mike D. Rogers, Republican of Alabama, said that “Congress must understand what happened and who made decisions to prevent the disclosure of the whereabouts of a cabinet secretary.”
Mr. Rogers said that he had scheduled a hearing for Feb. 14.
Mr. Austin, 70, has long been known as an intensely private man who eschews the limelight and dislikes talking to the news media — qualities that Mr. Biden was fine with, his aides said, when he appointed the 40-year Army officer to be his defense secretary.
But in keeping secret his hospitalization, Mr. Austin attracted more attention to himself than at any point in his long career. He also drew scrutiny and criticism of Mr. Biden’s national security team during a period when it was dealing with multiple crises around the world, including wars in Gaza and Ukraine.
After learning about Mr. Austin’s condition, Mr. Biden said he maintained confidence in his defense secretary but faulted him for waiting to notify the White House.