US President Donald Trump and House Speaker Nancy Pelosi have traded verbal blows after a fractious meeting at the White House.

Mr Trump said Ms Pelosi is a “third-grade” politician. She said he is having a meltdown.

A meeting between the two and others concerning Syria ended abruptly with a walkout by Ms Pelosi.

Against the backdrop of an impeachment inquiry, Ms Pelosi arrived not just as the leader of the opposing Democratic party, but as the speaker who could determine Mr Trump’s political future.

Trump
Nancy Pelosi (Alex Brandon/AP)

The House had just voted, 354-60, to overwhelmingly oppose the president’s announced US troop withdrawal, a rare bipartisan rebuke.

Mr Trump’s action has opened the door for a Turkish military attack on Syrian Kurds who have been aligned with the US in fighting the country’s long-running war.

The president began the meeting talking about his “nasty” letter to Turkish President Recep Erdogan, according to a Democrat familiar with the meeting who was granted anonymity to discuss it.

In the letter, Mr Trump warned the Turkish leader, with exclamation points, not to be “slaughtering” the Kurds. The person called Mr Trump’s opening a lengthy, bombastic monologue.

Ms Pelosi mentioned the House vote and Senator Chuck Schumer, the Democratic leader, started to read the president a quote from former Defence Secretary James Mattis on the need to keep US troops in Syria to prevent a resurgence of Islamic State fighters.

But Mr Trump cut Mr Schumer off, complaining that Mr Mattis was “the world’s most overrated general. You know why? He wasn’t tough enough.” Mr Trump reportedly went on, “I captured Isis.”

Ms Pelosi explained to Mr Trump that Russia has always wanted a “foothold in the Middle East,” and now it has one with the US withdrawal, according to a senior Democratic aide who was also granted anonymity.

“All roads with you lead to Putin,” the speaker said.

Mr Trump reportedly said to Ms Pelosi, “I hate Isis more than you do.”

Ms Pelosi responded, “You don’t know that.”

Mr Schumer intervened at one point and said, “Is your plan to rely on the Syrians and the Turks?”

Mr Trump replied, “Our plan is to keep the American people safe.”

Ms Pelosi said: “That’s not a plan. That’s a goal.”

Mr Trump turned to Ms Pelosi and complained about former President Barack Obama’s “red line” over Syria. According to Mr Schumer, he then called her “a third-rate politician”.

At that point Steny Hoyer of Maryland, the House Majority Leader, interjected, “This is not useful.”

Ms Pelosi and Mr Hoyer stood and left the meeting. As they did, Mr Trump said, “Goodbye, we’ll see you at the polls.”

From the White House driveway, Ms Pelosi told reporters Mr Trump was having some kind of “meltdown” inside. She said they had to leave because Mr Trump was unable to grasp the reality of the situation.

Later, she would insist he even botched the insult, calling her “third-grade” rather than “third-rate.”

The impeachment inquiry never came up, she said.

Mr Trump insisted later on Twitter that it was Ms Pelosi who had a “total meltdown,” calling her “a very sick person!”

He also tweeted pictures from the room. “Do you think they like me?” he asked mockingly about one, showing Ms Pelosi and Mr Schumer looking exhausted and glum.

“Nervous Nancy’s unhinged meltdown!” he tweeted with another.

In that photo, Ms Pelosi can be seen, surrounded by congressional leaders and military brass around a table at the White House, finger pointed.

Ms Pelosi turned the photo into the banner on her Twitter page.