U.S. Army Secretary Dan Driscoll and chief of staff General Randy George became the highest-level Trump Pentagon officials to visit Ukraine when they arrived on an unannounced trip this week, as Washington moves to deepen military tech ties with Kyiv.

The duo are slated to meet with Ukrainian military leaders, lawmakers and President Volodymyr Zelenskyy, starting Wednesday. The tour comes at a time when Russia has stepped up its deadly missile and drone campaign against civilian targets in Ukraine and western allies are scrambling to come up with new ways to keep supplying weapons to the embattled nation.

The U.S. and Ukraine have been working on a major deal to exchange drone and autonomous munitions technologies, and this trip in part is meant to bolster that effort. Ukraine has emerged as a leader in developing — and improving — long- and short-range armed drones that have changed the face of the battlefield and struck targets deep inside Russia.

The trip was described by two people familiar with the planning who were granted anonymity to discuss sensitive national security issues.

Spokespeople for Driscoll and George declined to comment.

Driscoll and George have used Ukrainian battlefield innovations as an example the U.S. defense industry and Pentagon should emulate in weapons development.

“When you look at Ukraine, [they] have not accepted the current version of a thing as sufficient, and they have MacGyvered and come up with whatever they have to do to get to an outcome they need,” Driscoll told reporters at the Pentagon this month.

“There are no rules to get to that outcome, and they just achieve the thing,” because they have to, he added. The Army has set a target to buy 1 million drones over the next two to three years, a goal that is far beyond the U.S. defense industry’s current capacity, while Ukraine is already producing more than 1.5 million first-person view drones each year.

The Trump administration has been hot and cold on its military support for Ukraine. Despite several trips to Europe, Defense Secretary Pete Hegseth has not traveled to Kyiv, though he has at least once moved to stop the flow of weapons to Ukraine, only to have the decision overturned by the White House.

During the Pentagon press conference this month, George, the Army’s top officer, added that in studying how Ukraine fights and adopts new technologies quickly, “what we picked up from them is really how you can go fast. And, you know, we’ve tried to replicate that” in Army rapid fielding and testing exercises.

Seeing top officials head to Kyiv to talk about weapons development and partnerships would have been unthinkable just a few months ago, after Trump and Vice President JD Vance got into a shouting match with Zelenskyy in the Oval Office.

Vance lashed out at the Ukrainian leader, saying he had not sufficiently thanked the U.S. for tens of billions in military aid, and Zelenskyy and Trump sparred over the direction of the conflict.

The argument came at the same time Hegseth traveled to Europe for the first time to tell NATO allies they needed to step up military spending because the United States had other priorities. That speech was followed by Vance’s comments to the Munich Security Conference lambasting Europe’s political culture.

The three events in rapid succession seemed to spell trouble ahead for U.S.-Europe relations and American support for Ukraine.

Since then, Trump has warmed to Zelenskyy and has enthusiastically backed NATO and its effort to arm Ukraine, as his efforts to engage in diplomacy with Russia have been rebuffed by Vladimir Putin. Meanwhile, Russia has continued to pound Ukraine with aerial attacks, firing 430 drones and 18 missiles into Kyiv on Friday.