Media playback is unsupported on your device Media caption How a meeting he wasn't at could hurt Donald Trump

US President Donald Trump's son has said his 2016 meeting with a Russian lawyer was about "essentially nothing" relevant to claims of collusion.

Donald Trump Jr called the media uproar over the meeting "the ultimate distraction" from his father's success.

Mr Trump Jr's meeting with a Kremlin-linked attorney at Trump Tower in New York could constitute a breach of US campaign rules, experts say.

The president argued the Trump Tower meeting was legal in a tweet on Sunday.

Mr Trump said his son took the meeting to "get information on an opponent", contradicting a previous statement from the Trump camp.

What did Trump Jr say?

Speaking on the Laura Ingraham Show on Monday night, the president's son said the meeting with lawyer Natalia Veselnitskaya lasted 20 minutes and primarily focused on Russian adoptions.

Mr Trump Jr has previously admitted he agreed to the introduction after he was promised damaging information about his father's Democratic rival Hillary Clinton.

He told Ingraham that adoptions were "the primary thing that we had spoken about in the meeting".

"You know that's not the premise that got them in the room... it was essentially a bait and switch to talk about that, and everyone has basically said that in testimony already," he said.

"It ended up being about essentially nothing that was relevant to any of these things. That's all it is and that's all they've got."

The president's eldest son also blamed Democrats for wanting to detract from his father's achievements.

"That is, I guess, the ultimate distraction from what's really going on in this country which is, you have a Republican president, a very conservative president, who is getting stuff done."

Image copyright Reuters Image caption Mr Trump Jr reiterated that the meeting in Trump Tower was about "essentially nothing".

Why is the meeting under scrutiny?

The meeting is being investigated by Special Counsel Robert Mueller as part of his inquiry into Russia's alleged role to help Mr Trump win the presidency.

Moscow has repeatedly denied claims it interfered in the November 2016 presidential elections.

President Trump and his son deny any collusion, and the president has tweeted that "collusion is not a crime".

Why does the president's Trump Tower tweet matter?

Mr Trump's Sunday tweet appears to contradict a previous statement from the Trump campaign about the meeting.

When the meeting was first reported by the New York Times, Donald Trump Jr said in a statement that he and Ms Veselnitskaya had mostly discussed a suspended programme for Americans to adopt Russian children.

However, he subsequently admitted he had agreed to the meeting after being told he would be offered information that would prove detrimental to Mrs Clinton. He also released the email exchange that brought about the meeting.

US media then reported that the US president had been involved in the initial statement his son issued on the meeting.

This was initially denied by Mr Trump's team, but his lawyers later confirmed that he had in fact dictated his son's statement.

US commentators have argued that Mr Trump's new admission that the meeting was to gain information about Mrs Clinton shows that the earlier statement was misleading.

Mr Trump again denied knowing about the meeting in Sunday's tweet.

Image copyright Reuters Image caption The meeting involved Mr Trump's son, his son-in-law, and then-campaign chairman Paul Manafort

Last month, however, Mr Trump's former lawyer Michael Cohen said the president knew about the meeting in advance.

The special counsel is currently investigating whether Mr Trump obstructed justice.

Under US law, obstruction cases require proving "corrupt intent" - so while Mr Trump's tweet does not prove anything illegal, it could serve as evidence of the president's intent.

Trump Tower meeting: How the story has changed

8 July 2017: The New York Times reveals the June 2016 meeting took place and Mr Trump Jr releases a statement describing it as a "short introductory meeting" that focused on Russian adoptions

The New York Times reveals the June 2016 meeting took place and Mr Trump Jr releases a statement describing it as a "short introductory meeting" that focused on Russian adoptions 9 July 2017: The Times reports that Mr Trump Jr was promised damaging information about Hillary Clinton before the meeting. He confirmed the report but said in a second statement that "no meaningful information" came from the meeting

The Times reports that Mr Trump Jr was promised damaging information about Hillary Clinton before the meeting. He confirmed the report but said in a second statement that "no meaningful information" came from the meeting 11 July 2017 : Mr Trump Jr tweets screenshots of his email correspondence that discussed setting up the meeting just minutes before the email chain was revealed in a Times story. The emails showed he was eager to accept "sensitive" information that was "part of Russia and its government's support for Mr Trump"

: Mr Trump Jr tweets screenshots of his email correspondence that discussed setting up the meeting just minutes before the email chain was revealed in a Times story. The emails showed he was eager to accept "sensitive" information that was "part of Russia and its government's support for Mr Trump" 12-16 July 2017: The president's lawyer Jay Sekulow denies that Mr Trump was involved in his son's initial statement to the Times

The president's lawyer Jay Sekulow denies that Mr Trump was involved in his son's initial statement to the Times 2 June 2018: The Times reports that Mr Trump's lawyers wrote a letter to special counsel Mueller acknowledging that he dictated his son's initial statement

The Times reports that Mr Trump's lawyers wrote a letter to special counsel Mueller acknowledging that he dictated his son's initial statement 26 July 2018: The president's former personal lawyer Michael Cohen says that Mr Trump approved the June 2016 meeting, contradicting previous statements by the Trump legal team

The president's former personal lawyer Michael Cohen says that Mr Trump approved the June 2016 meeting, contradicting previous statements by the Trump legal team 5 August 2018: The president says his son took the meeting "to get information on an opponent", but denies having any knowledge of it

Is Mr Trump Jr in legal jeopardy?

It is common for US politicians to research their opponents during a campaign.

But under US campaign law, it is illegal for a US citizen to solicit foreigners for campaign donations or contributions, even if such materials are never given.

Legal experts have debated whether Mr Trump Jr is guilty of conspiracy, since collusion is not a legal term.

Conspiracy is defined as if two or more people conspire to "commit any offence against" or "defraud" the US and one or more of the individuals "do any act to effect the object of the conspiracy".

It does not require the individuals to carry out the crime, just proof that it was agreed to.

Mr Trump Jr's email response to the offer of information about Mrs Clinton could breach those laws.

Some legal experts say, however, that calling information a "contribution or donation" may be a stretch.

While some say Mr Trump Jr broke the law by having the meeting, others maintain that it is unclear since he maintains no information exchanged hands at the meeting.

One of Mr Trump's lawyers, Jay Sekulow, said on Sunday that the meeting had not broken any laws.

"The question is what law, statute or rule or regulation's been violated? Nobody's pointed to one," Mr Sekulow told ABC News.