By Patricia Zengerle and Simon Lewis

WASHINGTON U.S. Secretary of State Antony Blinken said on Monday that a Senate delay in confirming President Joe Biden's nominees for diplomatic positions was undermining national security, echoing similar concerns from defense officials on delays to military promotions.

Blinken told reporters that he had sent a letter to every member of the Senate urging swift confirmation of dozens of nominees for State Department positions.

The nominations are being held back by Republican Senator Rand Paul while he seeks information from the administration on the origins of COVID-19.

"It strains credulity that some of the members of Congress calling most loudly for outcompeting our rivals are at the same time tying our hands behind our back. We cannot and we must not let this become the new normal," Blinken said.

The department said it currently has 62 nominees outstanding with the Senate, including 38 ambassadorial nominees.

Aides to Paul did not immediately respond to a request for comment.

Separately, nominations for more than 250 positions in the U.S. military are also being delayed by a single Republican - Senator Tommy Tuberville.

Tuberville began the holds in March to protest a Defense Department policy that provides paid leave and reimburses costs for services members who travel to get an abortion.

Most nominations are approved by Senate committees, and eventually reviewed by the full Senate, which is controlled by Biden's fellow Democrats. However, while confirmation for career diplomats to State Department positions and most military promotions are usually routine, a single senator can pause the process by putting a hold on nominations that force them to be considered one at a time, taking many hours each.

(Reporting by Patricia Zengerle and Simon Lewis; Editing by Rosalba O'Brien)