US President-elect Trump has conceded for the first time that Russia was behind the hacking of Democratic Party institutions during the presidential election, saying that not only Russia, but many other countries are hacking the US.

“I think it was Russia, but it's not just Russia,” Trump said Wednesday, during his first press conference since July, which was dominated by questions about Moscow's cyber attacks against US political organizations before the election.

On Friday, US intelligence agencies published a report accusing Russia of hacking Democratic Party emails to influence the US election, claiming that Russian President Vladimir Putin “sought to help” Trump defeat his Democratic rival Hillary Clinton.

The hacked emails, which were reportedly provided to WikiLeaks by individuals working for the Russian government, were a regular source of embarrassment to Clinton during the presidential race and may have contributed to her defeat.  

Trump criticized the cyber attacks during the press conference but said they revealed important information about Clinton.

“Hacking's bad, and it shouldn't be done...but look at what was learned from that hacking,” he said.

The hacked emails have raised questions about the real nature of the Clinton Foundation and showed how the former secretary of state sought to discredit his primary rival Vermont Senator Bernie Sanders to win the Democratic nomination.

Trump also said that other countries were easily hacking the US “because we have no defense.”

As an example, he claimed that China breached 22 million accounts in 2015 during a cyber attack against the US Office of Personnel and Management.

He pledged that all countries “will respect us, far more, far more than they do under past administration” after he is inaugurated on January 20.

Trump also described his warm relations with Putin as “an asset not a liability” and said while he hopes to get along with Putin well.

Later in the press briefing, Trump slammed media reports that Russia had obtained compromising personal and financial information about him and said the release of such details would amount to a “tremendous blot” on the record of the US intelligence community.