DONALD Trump has defended his “high-quality” son amid accusations that Donald Trump Jr’s meeting with a Russian lawyer was potentially in breach of federal law.

Hours after an appearance on Trump-friendly Fox News by Trump Jr, in which he discussed the controversial meeting, the president tweeted: “My son Donald did a good job last night. He was open, transparent and innocent”.

The comments come during a high-profile investigation by US officials into allegations of Russian meddling in the presidential election.

Trump Sr referred to ongoing allegations in his tweet as “the greatest Witch Hunt in political history”, while describing the scrutiny as “Sad!”

“My son is a high-quality person and I applaud his transparency,” the president said in a statement read to reporters by White House spokeswoman Sarah Huckabee Sanders.

Sanders declined to answer any questions, standing firm by the White House’s long-standing assertion that no one in Trump’s campaign colluded to influence the election.

Donald Trump Jr insists his father was never aware of a meeting he had with a Russian lawyer who promised him information on rival Hillary Clinton, which could “incriminate” her. “It was just a nothing. There was nothing to tell,” the president’s oldest son told Fox News Channel’s Sean Hannity.

An email exchange tweeted by Trump Jr – after the New York Times informed him they had obtained a copy — showed him conversing with British music publicist Rob Goldstone shortly before Trump Sr. clinched his Republican nomination.

Goldstone wanted him to meet with a “Russian government attorney” who supposedly had compromising information on Mrs Clinton as “part of Russia and its government’s support for Mr Trump”. “I love it,” Trump Jr replied. Although Trump Jr admitted “in retrospect I probably would have done things a little differently”, he maintained that despite being enticed by the prospect of discovering details of an “under-reported” scandal involving Clinton, the meeting “really went nowhere”.

Russian businessman Aras Agalarov and his pop-star son Emin – formerly managed by Goldstone – reportedly arranged the meeting.

In his email, Goldstone said the “crown prosecutor of Russia” offered to provide the information in a meeting with Aras Agalarov.

Russian officials have made efforts to distance themselves from the turbulent investigation.

President Vladimir Putin’s spokesman Dmitry Peskov told reporters in Moscow on Wednesday that the Kremlin has not spoken to Mr Agalarov and insisted that there are no ties to the Russian lawyer who was at the meeting.

Speaking on ABC’s Good Morning America and NBC’s Today, Trump’s lawyer joined the defence of the president’s son, saying he did not violate any laws in his meeting with the Russian lawyer.

Jay Sekulow said Trump snr was not aware of Trump Jr’s June 2016 meeting and did not find out about his son’s email exchange until “very recently”. He added that the president is not being investigated by special counsel Robert Mueller.

Democrats in Congress contend that the messages are evidence of collusion. California Representative Adam Schiff, the top Democrat on the House intelligence committee, argued that “all of the campaign’s previous denials obviously now have to be viewed in a different context”.

Republican members, meanwhile, remain non-committal. Senate majority leader Mitch McConnell said he was confident Senate investigators would “get to the bottom of whatever happened”.