The acting Pentagon chief and several other senior defense officials who were exposed to the novel coronavirus last week will not be quarantining, citing ongoing testing and safety precautions that appear to have been applied unevenly.

The officials, including acting defense secretary Christopher C. Miller, attended a meeting at the Pentagon on Nov. 13 with the Lithuanian defense minister, Raimundas Karoblis, whose embassy on Thursday said he had tested positive for the novel coronavirus, according to chief Pentagon spokesman Jonathan Hoffman.

Additional tests on Thursday showed that retired Brig. Gen. Anthony Tata, who performs the duties of the undersecretary of defense, also has the virus. He will isolate at home for the next 14 days, Hoffman said.

The Pentagon said others are tested, and did not disclose any other positive tests. Hoffman’s statement said the Pentagon recently “recommitted to fastidiously following” guidelines outlined by the Centers for Disease Control and Prevention, including “face coverings, social distancing, contact tracing, hand washing and virtual engagements."

Most of the Joint Chiefs of Staff quarantined early last month when Adm. Charles Ray, the vice commandant of the Coast Guard, tested positive for the virus after a meeting at the Pentagon. Gen. Gary L. Thomas, the assistant commandant of the Marine Corps, also later tested positive after attending the same meeting.

But the CDC guidelines have not been uniformly enforced since then, according to photographs, videos and other materials released by the Defense Department.

When Karoblis arrived at the Pentagon, he reached out to shake Miller’s hand, according to a report released by the Pentagon. Miller greeted him with an elbow bump “before committing to a handshake," the report said. The CDC does not recommend handshakes during the pandemic.

Defense Department photographs of the event show Karoblis greeting other Pentagon officials, including Tata, with elbow bumps. They sat at a large table with most people wearing masks, but Miller removed his, at least briefly.

Other photographs show social distancing at times, and some crowding at others. They also depict Miller shaking Karoblis’s hand a second time inside the Pentagon while both men wore masks.

Karoblis also met with Army Secretary Ryan McCarthy and Air Force Secretary Barbara Barrett on Nov. 13 and with Navy Secretary Kenneth Braithwaite on Monday, Hoffman said. All of them have since been tested for the coronavirus. The Pentagon did not disclose their results in a statement on Thursday night.

After meeting with Karoblis, Miller appeared in the Pentagon briefing room on Tuesday to announce troop reductions in both Iraq and Afghanistan. On Wednesday, he traveled to Fort Bragg, N.C., and to the USS Gerald R. Ford, an aircraft carrier in Norfolk. The Pentagon tests people making official trips before their departure.

Hoffman said the Pentagon is continuing to conduct contact tracing of Defense Department employees who came in close contact with the Lithuanian delegation or to Tata, “and are taking appropriate precautions.”

“Additionally, DoD personnel who had contact with the delegation have received or are receiving at this time rapid COVID tests as deemed necessary based on CDC protocols,” Hoffman said. “Additional necessary testing for individuals who had contact with Mr. Tata is ongoing. We will report additional positive cases as appropriate.”