A bipartisan delegation of five senators visiting U.S. troops in Afghanistan for the Independence Day holiday issued a stark warning about the Trump administration’s lack of strategy for a military conflict that has dragged on for more than a decade.

Sen. Lindsey Graham (R-SC) noted with concern that Trump’s Secretary of State Rex Tillerson has yet to visit the country, and the administration has not yet nominated an ambassador in Kabul.

“It’s more than just dropping bombs that will win in Afghanistan,” Graham said. “Secretary Tillerson needs to come to Afghanistan quickly.”

Six months into the Trump administration, Hundreds of State Department posts — including many that concern diplomatic strategy for the Middle East and Asia — likewise remain vacant. Sen. Sheldon Whitehouse (D-RI) said the military told him during the delegation that they have become alarmed by this “hollowing out of the State Department.”

The senators’ visit came just a few weeks after the Trump administration approved a large increase in the number of U.S. soldiers on the ground in Afghanistan, adding several thousand more to the roughly 9,000 currently stationed. But lawmakers from both parties slammed the lack of a “comprehensive” strategy that goes beyond military action.

“Nobody on the ground here believes there is a military-only solution,” said Sen. Elizabeth Warren (D-MA), the only other Democrat on the delegation.

“A solution needs to have a military angle, but also an economic and diplomatic plan,” she continued. “It needs to involved domestic political reconciliation, and it needs to be regional in nature, involving multiple countries in the area and account for external actors and influences. The administration owes it to the American people and to our men and women putting their lives at risk, to provide that clear vision of where we’re headed.”

Defense Secretary Jim Mattis offered an especially bleak picture of the Afghanistan at a Senate hearing in June, noting that “the enemy is surging.”

“The Taliban had a good year last year, and they’re trying to have a good one this year,” he said.