Updated July 13, 2017 01:36:44

US President Donald Trump has defended his eldest son as "innocent" following the release of emails that showed Donald Trump Jr welcomed Russian help against his father's rival in the 2016 presidential election.

On Tuesday, Mr Trump Jr released a series of emails that revealed he had eagerly agreed to meet with a Russian government lawyer who might have damaging information about Democratic rival Hillary Clinton.

"My son Donald did a good job last night. He was open, transparent and innocent. This is the greatest Witch Hunt in political history. Sad!" Mr Trump wrote on Twitter.

"Remember, when you hear the words "sources say" from the Fake Media, often times those sources are made up and do not exist."

The emails offered the most concrete evidence to date that Trump campaign officials embraced Russian help to win the election, a subject that has cast a cloud over Mr Trump's Presidency and spurred investigations by the Justice Department and Congress.

Mr Trump Jr's correspondence does not appear to provide evidence of illegal activity, but legal experts said he could run into trouble if investigators find he aided a criminal action, such as hacking into Democratic computer networks, or violated campaign laws.

In a Fox News interview later on Tuesday, Mr Trump Jr. said: "In retrospect, I probably would have done things a little differently."

President Trump, after initially releasing a statement on Tuesday calling his son "high quality", praised the television appearance and repeated his condemnation of investigations and media coverage of the Russia investigations.

Photo: Russia lawyer Natalia Veselnitskaya has denied having worked for the Russian Government. (AP: Yury Martyanov)

One of the President's personal attorneys, Jay Sekulow, in a round of TV interviews on Wednesday said Mr Trump Jr's meeting was not a violation of the law and that the President was unaware of the meeting and the emails until recently.

"There's no illegality," Mr Sekulow told NBC's Today program.

Mr Trump Jr also told Fox News Paul Manafort, Mr Trump's campaign manager at the time, and son-in-law Jared Kushner, now a top White House adviser, also attended the meeting with Russian lawyer Natalia Veselnitskaya, who has denied having Kremlin ties.

Moscow slams Trump Jr scandal

Meanwhile, Russia's Foreign Minister Sergei Lavrov has said it was preposterous that Mr Trump Jr was being blamed for meeting with Ms Veselnitskaya.

Photo: Russia's Foreign Minister Sergei Lavrov said it was "wild" that Mr Trump Jr was being targetted. (Reuters: Sergei Karpukhin, file)

Hitting back against accusations of Russian meddling in the elections, Mr Lavrov asked to be shown "at least one fact" proving Moscow tried to interfere with the democratic process.

"I learned with surprise that a Russian lawyer, a woman, is being blamed and Trump's son is being blamed for meeting," Mr Lavrov told a joint news conference with his Belgian counterpart in Brussels.

"For me, this is wild.

"Because when any person speaks to a lawyer, what problem or threat could there be? I didn't know about this, I learned about it from television."

Mr Lavrov dismissed the media interest in the email release, saying: "It's amazing that serious people are making a mountain out of a molehill."

Reuters/ABC

Topics: donald-trump, world-politics, security-intelligence, social-media, united-states, russian-federation, european-union

First posted July 12, 2017 23:54:14