Washington, Feb 9 (IANS): A Pentagon watchdog has found that ineffective implementation of social distancing and the premature release of sailors from quarantine were the primary causes of the massive Covid-19 outbreak onboard the USS Theodore Roosevelt aircraft carrier last year.

The Navy had appropriate plans in place to counter a potential outbreak of an infectious disease, but the leadership of the aircraft carrier did not fully implement the required measures, the Defence Department's Inspector General said in a report released on Monday.

The vessel's leadership also "allowed social gathering areas to remain open" and continued to conduct urine tests for illegal drugs despite the threat posed by Covid-19 and procedures outlined by the Navy, the report said.

The Roosevelt had just completed a port call in Da Nang, Vietnam, when it reported its first Covid-19 case on March 24, 2020.

At least 1,271 sailors of the 4,800-member crew aboard the aircraft carrier were infected with the virus last spring.

One crew member died.

Brett Crozier, the vessel's commander, wrote a letter to his superiors outlining the dire situation and pleading for help to evacuate the ship.

Crozier was relieved of his command after his letter leaked to the media.

The then-Acting Navy Secretary Thomas Modly said at the time that Crozier was removed because he sent the "non-secure unclassified email" to a "broad array of people".