The families of airmen who have completed boot camp will no longer be allowed to attend their graduation ceremonies, the U.S. Air Force announced Tuesday, adding yet another dramatic restriction to the growing list of measures the military has taken to contain the spread of the coronavirus.

The announcement came amid other news for the air service, including that cadets at the Air Force Academy would no longer be allowed to travel outside the U.S. to countries with heightened security risk for the spread of coronavirus, which causes a disease known as COVID-19. Air Force programs on future development that were to take place at South by Southwest in Austin, Texas, have been scrapped following the cancellation of the entrepreneurial and technology conference itself. And childcare at an airbase in Colorado has been shut down after a parent stationed there tested positive for the virus.

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Hours earlier on Tuesday the U.S. military headquarters overseeing operations in Africa announced it would cut parts of an ongoing exercise with forces from Morocco, Tunisia and Senegal, including all elements that involve troops' lodging in close quarters to one another.

"The safety and protection of our forces – U.S. and partner nations – is a priority," U.S. Africa Command's Gen. Stephen Townsend said in a statement.

An ongoing exercise in Europe known as Europe-Defender 20 involving tens of thousands of allied forces and including 20,000 Americans was proceeding as planned as of Tuesday morning, officials say. No changes have occured yet due to the coronavirus.

The troubling spread of the virus worldwide has posed particular challenges for the far-flung U.S. military as it struggles to contain infection among its forces and employees while maintaining a warfighting posture abroad.

"Our assessment at this point is we have not yet seen any dramatic reduction in readiness of ... our forces with regard to COVID," Jonathan Hoffman, a Pentagon spokesman, told reporters Tuesday afternoon.

Navy Rear Adm. William Byrne of the Joint Staff said at the same briefing that the military was encouraging small-group exercises and operations but that larger scale events may be modified.

When asked about whether the spread of the virus would affect summertime deployments when large numbers of U.S. forces relocate to various posts around the world, including on the Korean peninsula, Hoffman said, "We haven't decided on a department-wide policy yet."

Organizers for the Pentagon press conference positioned journalists in the briefing room with " social distancing " as a part of attempts within one of the largest office buildings in the world to prevent the spread of the virus. Concerns remain as to whether staffers there could accommodate a widespread outbreak that forces unprecedented numbers to work remotely.