US President Donald Trump's son has said he did not tell his father about a meeting with a Russian lawyer who said she could help his election campaign.

Donald Trump Jr told Fox News the meeting was "just a nothing" but he should have handled it differently, a BBC report said.

He released emails showing he welcomed an offer to meet the lawyer, who was allegedly linked to the Kremlin and had material damaging to Hillary Clinton.

US officials are investigating alleged Russian meddling in the US election.

White House deputy press secretary Sarah Huckabee Sanders read a statement from the President defending his son. "My son is a high-quality person and I applaud his transparency," Sanders said, reading a statement from Trump.

"Beyond that I'm going to have to refer everything beyond this matter to Don Jr.'s counsel and outside counsel," Sanders said.

Since he was elected, President Trump has been dogged by allegations that Russia tried to sabotage Mrs Clinton's campaign.
He has denied any knowledge of this and Russia has also repeatedly denied interfering.

The emails are the most concrete evidence yet that Trump campaign officials welcomed Russian help to win the election, a subject that has cast a cloud over Trump's presidency and spurred investigations by the Justice Department and Congress, a Reuters report said.

The messages show that the younger Trump was open to the prospect of "very high level and sensitive information" from a Russian attorney that a go-between described as "part of Russia and its government's support for Mr. Trump" ahead of a meeting on June 9, 2016.

"If it's what you say I love it," Trump Jr. responded. He released the messages on Twitter after the New York Times said it planned to write about them and sought comment from him.

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

He said Veselnitskaya did not provide any damaging information about Clinton at the meeting and instead sought to discuss Russian sanctions.

"In retrospect, I probably would have done things a little differently," he said. "For me, this was opposition research."

Nevertheless, the correspondence between him and Rob Goldstone, a publicist who arranged the meeting, could provide fodder for US investigators probing whether Trump's campaign colluded with the Kremlin.

"The crown prosecutor of Russia ... offered to provide the Trump campaign with some official documents and information that would incriminate Hillary and her dealings with Russia and would be very useful to your father," Goldstone wrote Trump Jr. on June 3. Russia does not have a "crown prosecutor" - the equivalent title is prosecutor general.

US intelligence agencies have concluded that Moscow sought to help Trump win the election, in part by releasing private emails from Democratic Party officials.

"The conversation will now turn to whether President Trump was personally involved or not. But the question of the campaign’s involvement appears settled now," Cornell Law School professor Jens David Ohlin said in an interview.

"The answer is yes."