KABUL, Afghanistan — A delegation of United States senators visiting Afghanistan issued a stark warning on Tuesday to President Trump to fill vacant embassy and State Department positions here in order to better address the country’s mounting military and political crises.

Led by Senator John McCain, Republican of Arizona, the American delegation in Kabul voiced what has been a concern for months now in the absence of a permanent American ambassador. The civilian diplomatic mission here has been led by a chargé d’affaires, Hugo Llorens, who was called in from imminent retirement to help as a stopgap during a time when the Afghan government has faced political storms.

“All of us realize that it’s more than just dropping bombs that will win in Afghanistan,” Senator Lindsey Graham, Republican of South Carolina, said. “Secretary Tillerson needs to come to Afghanistan quickly.”

Mr. Graham described the lack of diplomatic focus as unnerving and called on the administration to appoint someone “to manage this portfolio” as well as fill many of the vacant positions in the State Department dealing with South and Central Asia.