WASHINGTON — A meeting between President Donald Trump’s eldest son and a Russian lawyer during the presidential campaign occurred at the behest of a Moscow-based singer with family ties to Trump’s businesses, according to a participant in the talks. Donald Trump Jr. acknowledged Monday he made time for the meeting hoping to get information about Democrat Hillary Clinton.

The circumstances surrounding the meeting fueled new questions about the Trump campaign’s possible ties to Russia, which are being scrutinized by federal and congressional investigators. Some election law experts said a discussion of potentially damaging information on Clinton could prompt scrutiny from Special Counsel Robert Mueller in light of federal laws barring foreign contributions to campaigns.

Larry Noble, a former general counsel at the Federal Election Commission, said the situation “raises all sorts of red flags.”

“You do not want your campaign to be involved with foreign nationals, period,” said Noble, now senior director at the Campaign Legal Center.

On Monday, Trump Jr. tried to brush off the significance of the meeting, tweeting 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.”

Hours later, New York-based attorney Alan Futerfas said he had been retained to represent the president’s son. And Trump Jr. said on Twitter he was willing to work with the Senate intelligence committee, one of the panels probing possible campaign collusion, “to pass on what I know.”

Lawmakers on the committee from both parties said they indeed wanted to talk with the president’s son. Sen. Susan Collins, R-Maine, said the panel “needs to interview him and others who attended the meeting.”

The sequence of events that led to the June 2016 meeting highlighted the tangled web of relationships that investigators now are sorting through.

The president’s son said the meeting was arranged by an acquaintance he knew through the 2013 Miss Universe pageant Trump held in Moscow.

Trump Jr. didn’t name the acquaintance, but in an interview with The Associated Press, music publicist Rob Goldstone confirmed he set up on the meeting on behalf of his client, Russian singer Emin Agalarov. Goldstone said the Russian lawyer stated that she had information about purported illegal campaign contributions to the Democratic National Committee that she thought Trump Jr. might find helpful.

Goldstone said Trump Jr. agreed to squeeze the meeting into a tight schedule.