US President defends son after emails over Russian campaign help

On Tuesday, Trump Jr. released a series of emails that revealed last year he eagerly agreed to meet a woman he was told was a Russian government lawyer who might have damaging information about Democratic rival Hillary Clinton as part of Moscow's official support for his father.

Trump Jr., in a Fox News interview later on Tuesday, said: "In retrospect, I probably would have done things a little differently."

The president, after initially releasing a statement on Tuesday calling his son "high-quality," on Wednesday praised the television appearance and repeated his condemnation of investigations and media coverage of the Russia investigations.

"He was open, transparent and innocent. This is the greatest Witch Hunt in political history. Sad!" Trump wrote on Twitter.

The emails offered the most concrete evidence to date that Trump campaign officials embraced 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.

Trump Jr.'s correspondence does not appear to provide evidence of illegal activity, but legal experts said he could run into trouble if investigators find he aided a criminal action, such as hacking into Democratic computer networks, or violated campaign finance laws by accepting gifts from foreign entities.

The latest developments jarred financial markets as investors worried it was another distraction from the administration's economic agenda.