Donald Trump sharply criticized NATO once again following a closed-door meeting with Secretary General Mark Rutte at the White House, accusing the alliance of failing to back the United States during the Iran conflict.

In a post shared to Truth Social after the meeting, the US President said: "NATO WASN'T THERE WHEN WE NEEDED THEM, AND THEY WON'T BE THERE IF WE NEED THEM AGAIN."

Rutte, however, offered a more measured account of the discussion, telling CNN the conversation with Trump was "very frank" and "very open," even as differences between the two sides remained evident.

Before the talks on Wednesday, Trump had raised the possibility of withdrawing from the transatlantic alliance, frustrated by resistance from several NATO members to his push for assistance in reopening the Strait of Hormuz amid surging global oil prices.

Officials at the White House declined to provide specifics about what was discussed.

Rutte spent more than two hours at the White House on Wednesday, though the exact duration of his direct meeting with Trump has not been confirmed.

The meeting had been seen as an effort to persuade Trump that continued US participation in NATO aligns with both his own interests and those of the country.

Despite that effort, Trump’s skepticism toward the alliance appears undiminished, particularly toward member states he believes offered insufficient support before and during Operation Epic Fury.

In recent weeks, the president has repeatedly floated the idea of pulling the US out of the 32-nation alliance.

Addressing NATO’s involvement in the Iran conflict, White House Press Secretary Karoline Leavitt said Wednesday, quoting Trump directly, that the alliance had been "tested and they failed".

Leavitt added that NATO countries had "turned their backs on the American people," whose contributions underpin their defense capabilities, and said Trump intended to hold a "very frank and candid conversation" with Rutte.

Rutte, for his part, emphasized that European allies had contributed in various ways, even if not uniformly.

He told CNN that he pointed out that "the large majority of European nations has been helpful with basing, with logistics, with overflights".

"It's therefore a nuanced picture," Rutte said.

Whether that argument — along with Rutte’s personal rapport with Trump — will be enough to shift the president’s stance remains unclear.

When asked if global security had improved since the Iran conflict began, Rutte said "absolutely" and credited that to Trump's "leadership" in degrading Iran's nuclear threats.

He also noted that NATO members generally do not view the war in Iran as unlawful and that most agreed on the need to weaken Tehran’s nuclear capabilities.

Legal constraints remain in place for any US withdrawal. At the end of 2023, Congress approved a measure barring a president from exiting NATO without either a two-thirds Senate majority or legislation passed by Congress.

Tensions between the Trump administration and NATO were already high before the Iran conflict, driven in part by disputes over Trump’s ambitions regarding Greenland.

Trump referenced that issue in his Truth Social post following the meeting, writing: "REMEMBER GREENLAND, THAT BIG, POORLY RUN, PIECE OF ICE!!!"

Still, the Iran conflict has intensified those disputes, pushing Trump’s grievances with NATO to new levels and presenting what may be one of the most serious tests in the alliance’s history.