NATO chief appeared to downplay the rare absence of Secretary of State Marco Rubio at what is meant to be a gathering of allies at a key moment in the U.S.-led pefforts.
The countries "of concern" include Afghanistan, Haiti and Venezuela, among others. The announcement comes a day after an attack on National Guard troops.
Even as he increases military pressure, Trump has said that he could still hold talks with Venezuela's president, suggesting a possible diplomatic off-ramp.