WASHINGTON — Mark Esper will spend his first week as acting secretary of defense in Belgium.

Late Wednesday evening, the Pentagon announced that Esper, who was tapped this week to replace Patrick Shanahan as the department’s top official, will travel to NATO for next week’s defense ministerial.

“As previously announced, Secretary of the Army, Dr. Mark Esper, will become the Acting Secretary of Defense on Monday, June 24 at 12:01 a.m. He will travel to the NATO Defense Ministerial in Brussels, Belgium later that week,” chief Pentagon spokesman Jonathan Hoffman wrote in a statement.

How long will it take to get a new defense secretary now? With Patrick Shanahan's sudden withdrawal to take over the Pentagon, military leaders could wait months for a replacement.

Shanahan had been planning to go to the meeting, a semi-regular gathering of the alliance defense ministers, before the shocking Tuesday announcement that he would be leaving the Pentagon following the surprise revelation of family domestic abuse issues.

But there had been speculation that Esper, the current secretary of the Army, would skip the meeting in favor of another defense official, perhaps Acting Deputy Secretary of Defense David Norquist or Undersecretary of Defense for Policy John Rood.