WASHINGTON (AP) — House Speaker Mike Johnson is calling on Ukrainian President Volodymyr Zelenskyy to fire his country’s ambassador to the U.S. as Republicans criticize Zelenskyy’s visit to an ammunition plant in Pennsylvania, a swing-state, as a political stunt.

The Republican speaker’s demand Wednesday came as Zelenskyy addressed the United Nations in New York on the eve of his visit Washington, where he has plans to brief lawmakers on Capitol Hill about the war effort before meeting with President Joe Biden at the White House.

“The tour was clearly a partisan campaign event designed to help Democrats and is clearly election interference,” Johnson wrote in a letter to Zelenskyy.

Johnson, who is close to Republican presidential nominee Donald Trump, said no Republicans were invited to the plant tour on Sunday, which he said was arranged by Ambassador Oksana Markarova.

An Army official said it was standard procedure to invite House and Senate members who represent the district where such industrial plants are located. The official, who spoke on condition of anonymity to discuss internal discussions, said that in this case interested congressional members from the area attended.

Joining for the visit were the state’s Gov. Josh Shapiro, Sen. Bob Casey and the district’s Rep. Matt Cartwright, all Democrats. The plant is located in Scranton, Biden’s hometown.

The speaker’s stern demand for the swift removal of Markarova, a well-received diplomat in Washington who has been a fixture on Capitol Hill since the outset of the war — even sitting as a guest in the House visitor’s gallery during pivotal speeches — comes at a daunting time for Ukraine as Zelenskyy works to ensure U.S. support for the war effort in an election year.

While Biden and Democrats in Congress have largely stood with Ukraine since the Russian invasion in 2022, sending billions in U.S. aid to buy weaponry and support services, Republicans have split deeply. Trump has turned the GOP toward a new America First movement that generally prefers to limit U.S. involvement overseas, and he often speaks admirably of Russia and its president, Vladmir Putin.

Johnson said that support for ending Russia’s war against Ukraine “continues to be bipartisan, but our relationship is unnecessarily tested,” noting comments from the Ukrainian government about the top of the Trump-Vance presidential ticket.

Trump in his own speech Wednesday lashed out at Zelenskyy and said the people of Ukraine are “dead” and the country itself “demolished,” raising fresh questions about the level of U.S. support the former president would provide to help Ukraine fight Russia if he returned to the White House.

Later Johnson, who said he won’t be meeting Thursday with Zelenskyy at the Capitol, said the ambassador “crossed the line” and the situation requires “immediate attention and action.”

Zelenskyy visited the Scranton Army Ammunition Plant to thank the workers who are producing one of the most critically needed munitions for his country’s fight to fend off Russian ground forces.

The Scranton plant is one of the few facilities in the country to manufacture 155 mm artillery shells and has increased production over the past year. Ukraine has already received more than 3 million of them from the U.S.

“It is in places like this where you can truly feel that the democratic world can prevail,” Zelenskyy wrote on X.

“Thanks to people like these — in Ukraine, in America, and in all partner countries — who work tirelessly to ensure that life is protected.”

Zelenskyy is far from the first foreign leader to visit U.S. plants producing and selling arms to their country, in tours that did not incur Republican protests. The U.S.’s NATO partners in Europe increasingly have made a point of such visits to demonstrate the jobs and money that U.S. alliances bring home to Americans.

Zelenskyy also has met exclusively with Republicans on some past trips while in the U.S. In July, he visited Utah to speak at the National Governor’s Association and was welcomed by the state’s Republican Gov. Spencer Cox, the group’s outgoing chairman. During the visit Zelenskyy also met with Utah’s congressional delegation, all Republicans.

The Scranton visit sparked swift reprisals from the Republicans.

Rep. James Comer, the Republican chairman of the House Oversight Committee, announced Wednesday he was opening an investigation into whether the Biden-Harris administration used taxpayer-funded resources to fly Zelenskyy to Pennsylvania as a campaign event for Vice President Kamala Harris, who is the Democratic nominee for president.

“The Committee seeks to determine whether the Biden-Harris Administration attempted to use a foreign leader to benefit Vice President Harris’s presidential campaign and, if so, necessarily committed an abuse of power,” he wrote in letters to Biden, the White House counsel and others in the administration.

The Pentagon said the flight was funded by the Defense Department for senior officials from the departments of Defense and State “conducting official business related to U.S. security assistance to Ukraine.” The flight stopped at Newark Liberty International Airport, “where they linked up with President Zelensky before continuing to Wilkes-Barre International Airport in Pennsylvania,” the Pentagon said.

Senate Republicans, even those who had supported aid for Ukraine, roundly criticized Zelenskyy on Wednesday. “He really messed up,” said Sen. Markwayne Mullin, an Oklahoma Republican.

However, Sen. Roger Wicker, the top Republican on the Senate Armed Services Committee and a firm backer of Ukraine, suggested that Zelenskyy’s visit was not as partisan as it appeared. Wicker was planning to meet with the Ukrainian president at the Capitol on Thursday.

“If President Zelenskyy came to Mississippi, he would be accompanied by Republican officials because that’s who the people in their wisdom elected,” he said.

___

Associated Press writers Stephen Groves and Lolita C. Baldor in Washington and Michael Rubinkam in northeastern Pennsylvania contributed to this report.