The president spoke to pool before a working lunch with budget advisers in Roosevelt Room.
"We must do a lot more with less," he said, promising to end waste and to continue to renegotiate federal contracts. "We have already saved a lot – billions and billions of dollars."
"The finances of this country are a mess but we're going to clean that up," he said.
"I will be holding everybody accountable for that," he said, expressing confidence in his team.
"We're going to take this budget which is in all fairness I've only been here for four weeks so I can't take too much of the blame for what's happened but it is absolutely out of control," Trump said.
He said the federal debt had doubled in a very short time.
He promised to do "tremendous" things with the budget, taking care of military, in particular. He promised a health care plan in March, "maybe mid to early March we'll be submitting something that I think people will be very impressed by."
He sat between OMB director Mick Mulvaney on his right and Treasury Secretary Steven Mnuchin on his left. "He's going to be an absolutely great director," Trump said of Mulvaney.
Pool set up before Trump arrived at 12:38. He greeted Mnuchin and others, then invited them to sit down. He made his statement and took no questions. All places were set with iced tea and water except for Trump's which was set only with water.
Also seated at the table: Jared Kushner, Emma Doyle and Russ Vought of OMB, Steven Miller, economic adviser Gary Cohn, Reince Priebus, Steve Bannon.
Pool ushered out five minutes after Trump arrived.