President Donald Trump's eldest son says he met a Russian lawyer during the 2016 presidential campaign to hear information about his father's Democratic opponent, Hillary Clinton.

Donald Trump Jr on Monday tweeted sarcastically, "Obviously I'm the first person on a campaign to ever take a meeting to hear info about an opponent ... went nowhere but had to listen."

Obviously I'm the first person on a campaign to ever take a meeting to hear info about an opponent... went nowhere but had to listen. https://t.co/ccUjL1KDEa

— Donald Trump Jr. (@DonaldJTrumpJr) July 10, 2017

Trump Jr's acknowledgement came as a music publicist told The Associated Press that he set up the meeting on behalf of a client in Moscow named Emin Agalarov, the son of a Moscow-based developer who tried to partner with Trump in a hotel project.

The publicist, Rob Goldstone, said in a statement that the Russian lawyer said she had information about purported illegal campaign contributions to the Democratic National Committee that she thought Trump Jr might find helpful.