House Republicans are launching an investigation into President Zelensky of Ukraine and the Biden administration’s role in using taxpayer dollars to bring him to the critical battleground state of Pennsylvania ahead of the presidential election, where he recently appeared alongside Governor Shapiro and Senator Casey at an Army base responsible for weapons manufacturing.

Republicans say the stop was nothing less than a campaign event for Vice President Harris. 

The probe, led by the House Oversight Committee and Chairman James Comer, is seeking information about Mr. Zelensky’s trip to the Scranton Army Ammunition Plant alongside the prominent Democrats. He is in America for the meeting of the United Nations General Assembly, and made the short trip to Pennsylvania on Monday. 

“Chairman Comer today is opening an investigation into the Biden-Harris Administration using taxpayer-funded resources to fly Ukrainian President Volodymyr Zelensky to Pennsylvania to campaign for Vice President Kamala Harris ahead of the 2024 presidential election,” the Oversight Committee said in a statement. Republicans say the visit is a more grave example of election interference than President Trump’s call to Mr. Zelensky in 2019 when he asked that the Ukrainian leader open an investigation into President Biden and his son, Hunter. 

A spokesman for the Ukrainian Ministry of Foreign Affairs did not immediately respond to a request for comment about the investigation. 

Mr. Comer says sending Mr. Zelensky to Pennsylvania is especially egregious because of the importance of the state in the November election. “If the Biden-Harris Administration attempted to use a foreign leader to benefit the Vice President’s presidential campaign, this is an abuse of power and misuse of taxpayer dollars,” the committee says. 

In letters sent to Attorney General Garland, Defense Secretary Austin, and White House Counsel Ed Siskel, Mr. Comer demands that they turn over information about the motivations of sending Mr. Zelensky to the Pennsylvania armory, and to examine if any ethics or campaign finance rules had been violated. 

The committee points specifically to a recent interview Mr. Zelensky did with the New Yorker, where he referred to Senator Vance as being “too radical” to serve as vice president because of his position on the Russia–Ukraine war, which Republicans say is just another example of potential election interference. Mr. Zelensky said Mr. Vance’s plans are to force Ukraine to “give up our territories.”

“His message seems to be that Ukraine must make a sacrifice. This brings us back to the question of the cost and who shoulders it. The idea that the world should end this war at Ukraine’s expense is unacceptable,” the Ukrainian president said. “I do not consider this concept of his a plan, in any formal sense. This would be an awful idea, if a person were actually going to carry it out, to make Ukraine shoulder the costs of stopping the war by giving up its territories.”

Mr. Casey, who himself is facing a tough reelection bid this year, told Punchbowl News after the committee’s announcement that Mr. Comer’s move is “desperate” and “insulting.”

Speaker Johnson went one step further than Mr. Comer on Wednesday, writing directly to Mr. Zelensky to demand he fire his own ambassador to Washington following the Pennsylvania visit. Mr. Johnson called his decision to visit Pennsylvania a “shortsighted and intentionally political move” that was “clearly election interference.”