​President Biden lost his temper and raised his voice on the phone with​ Volodymyr Zelensky when the Ukrainian leader continued to press for more aid even after Biden signed off on $1 billion worth of military assistance, according to a report Monday. ​

The phone call in June, one of many between the two leaders, turned testy ​shortly after Biden announced the $1 billion aid package, Zelensky began listing what else Kyiv needed and wasn’t getting, NBC News reported.​

The commander-in-chief lost his temper ​and, with his voice rising, reminded Zelensky of the generosity of the American people, stressing the point that his administration​ and ​the US military w​ere doing all ​they could to help Kyiv in its war with Russia. 

H​e told Zelensky that he should be more thankful.​

Another source disputed that the call was heated, saying Biden was direct with Zelensky and addressed his concerns in the appropriate military channel.

The relationship between Biden and Zelensky improved after the June call, and the Ukrainian leader released a statement thanking the US for its contribution to the war effort, the report said.

A spokesperson for the National Security Council declined to comment after being contacted by NBC News. 

A Zelensky spokesperson didn’t respond to a request for comment.​

The president’s frustrations had been ​rising for weeks before the June 15 call, and Biden confided to aides that he believed his administration was pulling out all stops to help Ukraine, but that Zelensky continued to focus on what wasn’t being done. 

But the report said some Eastern European governments and US politicians were annoyed that the Biden administration took too long to OK weapons requests – to the point of delaying some of Ukraine’s pleas and then giving in weeks or months later as pressure mounted. 

Zelensky’s advisers, immediately after the June call, worked to resolve any lingering tensions, deciding that it wouldn’t be useful to be at odds with Biden. 

Zelensky went public with his appreciation the same day. 

“I had an important conversation with US President Biden today,” Zelensky said in videotaped remarks. “I am grateful for this support. It is especially important for our defense in Donbas.”

Biden in a statement noted that he had informed Zelensky of the $1 billion in aid and assured him that the US “will not waver in our commitment to the Ukrainian people as they fight for their freedom.”

The US has provided about $20 billion in aid to Ukraine since Russia invaded in February.