NEW YORK — President-elect Donald Trump’s first news conference since winning the election was a combative and freewheeling affair, and the famously unconventional politician demonstrated he had not been changed by the weight of his victory.

Trump said for the first time Wednesday he accepts that Russia was behind the election-year hacking of Democrats that roiled the White House race. Looking ahead, he urged Congress to move quickly to replace President Barack Obama’s signature health care law and insisted anew that Mexico will pay the cost of a border wall.

He defiantly denied reports that Russia had collected compromising personal and financial information about him, lambasting the media for peddling “fake news” and shouting down a journalist from CNN, which reported on the matter. His family and advisers clapped and cheered him on throughout.

Trump’s transition has been overshadowed by U.S. intelligence assessments that Russia not only meddled in the election, but did so to help him defeat Democrat Hillary Clinton. After spending weeks challenging that idea, Trump finally accepted at least part of the intelligence conclusions.

“As far as hacking, I think it was Russia,” Trump said, quickly adding that “other countries and other people” also hack U.S. interests. Still, he kept needling the intelligence agencies, saying it would be a “tremendous blot” on their record if officials were leaking information from his classified briefings.

Director of National Intelligence James Clapper said in a statement later that he had spoken with Trump Wednesday evening and told him he does not believe any leaks came from the intelligence community.

Trump has not said whether he believes Clapper’s claim about the source of the leaks. He tweeted Thursday: “James Clapper called me yesterday to denounce the false and fictitious report that was illegally circulated. Made up, phony facts. Too bad!”

One U.S. official told The Associated Press Tuesday night that intelligence officials had informed Trump last week about an unsubstantiated report that Russia had compromising personal and financial information about him. The official was not allowed to publicly discuss the matter and spoke on condition of anonymity.