US President Donald Trump says he was “very surprised” and “disappointed” with former ally Elon Musk’s criticisms of his centrepiece budget bill.

“Elon and I had a great relationship. I don’t know if we will anymore,” Trump told reporters in the White House on Thursday.

It was the president’s most direct criticism yet of Musk’s lobbying efforts against the proposals to cut taxes and slash government spending – a plan that has drawn criticism from Musk and some Republicans.

In response, Musk doubled down on X and accused the president of “Such ingratitude”, adding: “Without me, Trump would have lost the election”.

Musk left his post at the Department of Government Efficiency last week after 129 days on the job, and Trump presented him with a with a golden key during a congratulatory news conference on 30 May.

But in the days since, he has repeatedly criticised Trump’s budget bill currently working its way through Congress, calling it a “disgusting abomination” and posting “Shame on those who voted for it: you know you did wrong.”

The bill passed the House with the backing of most Republicans, with a handful of representatives from Trump’s party and all Democrats opposed.

Speaking to reporters during a news conference with German Chancellor Friedrich Merz on Thursday, Trump said: “We are doing things in that bill that are unbelievable.

“I’m very disappointed because Elon knew the inner workings of this bill better than almost anybody sitting here,” he said. “All of a sudden he had a problem.”

“He hasn’t said bad about my personally, but I’m sure that will be next.”

Put in charge of radically slashing government spending, Musk initiated mass sackings and wholesale elimination of departments such as the US Agency for International Development (USAID).

Doge claims to have saved $180bn, although that number has been disputed, and is well short of Musk’s initial aim to cut spending by up to $2 trillion.