The Ukrainian government has informed the White House that it plans to fire the country’s top military commander overseeing the war against Russian occupation forces, two knowledgeable sources said on Friday.

The move to oust General Valeriy Zaluzhnyi, who has clashed with President Volodymyr Zelenskyy over a range of issues, follows a Ukrainian counteroffensive last year that failed to recover significant amounts of Russian-held territory.

A source close to Zelenskyy’s office said the pair are locked in a dispute over a new military mobilization drive, with the president opposing Zaluzhnyi’s proposal to call up 500,000 fresh troops.

The source, however, added that the process for relieving Zaluzhnyi of his post as the commander in chief of Ukraine’s armed forces was on hold for the time being as the sides work out their next steps.

It was unclear how long that process would take, added the source, who spoke on condition of anonymity.

A second knowledgeable source said that the White House did not express a position on the plan to replace Zaluzhnyi.

“I would emphasize that the White House response was that we did not support or object to their sovereign decision,” said the source, who requested anonymity in order to discuss the issue.

“The White House expressed that it is up to Ukraine to make its own sovereign decisions about its personnel,” the source continued.

The Washington Post was first to report that Ukraine had informed the White House of the plan to fire Zaluzhnyi.

US officials told Ukraine that they were not opposed to the firing of Zaluzhnyi, said the source close to the Ukrainian president’s office.

“The US is okay with Ukraine firing him,” said the source.

“Right now, both sides (the president and the general) have taken a pause in determining what the future will look like, and for now the status quo will remain until further notice,” the source said.

The source said the frictions between Zelenskyy and Zaluzhnyi over mobilization involved the president’s view that the military has enough personnel that could be used more efficiently.

“Zaluzhnyi insists on mobilizing half a million men. Zelenskyy thinks that’s not necessary now,” the source said.

Zaluzhnyi on Thursday published a column on the CNN website in which he wrote that the government had failed to mobilize enough troops.

Known as “the Iron General,” Zaluzhnyi is extremely popular. His removal could hurt morale among Ukrainian troops battling to hold positions along more than 620 miles (1,000 km) of frontlines against a vast Russian force armed with large munitions stockpiles.

Ukrainian forces are experiencing shortages of critical ammunition. Supplies from the United States, the country’s largest arms provider, have run down, and a dispute between the White House and some Republican lawmakers has stalled approval of a new aid package.

A flurry of Western and Ukrainian media reports said that Zaluzhnyi rejected Zelenskyy’s request that he step aside this week.

The plan to replace Zaluzhnyi despite his popularity and ability as an inspiring commander may signal Kyiv’s desire for a fresh approach to the conflict.