White House officials tell senators that Ukraine is committed to anti-corruption.

Senior Biden administration officials told senators on Thursday that a shake-up in Ukraine’s government was an encouraging sign of President Volodymyr Zelensky’s commitment to anti-corruption efforts and assured worried senators that there is no evidence of stolen or diverted U.S. aid.

On Tuesday, several top Ukrainian officials were fired or forced to resign following allegations of government corruption, including reports that Ukraine’s military had agreed to pay inflated prices for food meant for its troops.

One of three Biden officials testifying before a Senate Foreign Relations Committee hearing on Ukraine, Victoria Nuland, the under secretary of state for political affairs, said that the shake-up in Kyiv “sends a very strong signal to others who would try to rip off this war effort, and is important for the future of Ukraine.”

“We have been very clear that we need to see, as they prosecute this war, the anti-corruption steps, including good corporate governance and judicial measures, move forward,” she added.

Ms. Nuland was responding to a question from Senator Jeff Merkley, Democrat of Oregon, who said he was worried that corruption within Ukraine’s government could be “a kind of cancer eating away at support that they need from everyone in the world.”

While admitting that it is difficult to monitor arms and money in a country gripped by war, U.S. and European officials have so far spun the drama in Kyiv as proof that Mr. Zelensky, who campaigned for president as a bold corruption fighter, remains committed to that goal.

Celeste Wallander, the assistant secretary of defense for international security affairs, told the Senate committee that the administration “has not seen credible evidence of any diversion of U.S.-provided weapons outside of Ukraine.”

Erin McKee, an assistant administrator with the U.S. Agency for International Development, said the United States is using “extraordinary measures” to track nonmilitary funding.

Some senators, including the committee’s Democratic chairman, Bob Menendez of New Jersey, questioned whether the Biden administration had a clear plan for the war in Ukraine.

“In the immediate term, I think there is a question that needs to be answered: What is your strategy for helping Ukraine achieve victory?” asked Mr. Menendez, who said the United States has been slow to deliver key weapons systems to Kyiv.

Questions about the growing price tag of America’s economic and military support for Kyiv also emerged.

“Many Americans, certainly many Tennesseans that talk to me, are very concerned about a type of open-ended commitment to Ukraine,” said Senator Bill Hagerty, Republican of Tennessee, who asked for “a clearer picture of where we’re headed.”