US presidential candidate Robert Kennedy Jr. will announce his candidacy as an independent instead of continuing his long-running bid to defeat President Joe Biden as the Democratic nominee, complicating next year’s presidential election.

Kennedy, an anti-vaccination activist and member of a famous American political family, posted a video on YouTube on Friday asking Americans to join him in a “major announcement” in Philadelphia on October 9.

He said he would talk about a radical change in American policy.

Kennedy is the nephew of former President John F. Kennedy, who was assassinated in 1963, and the son of former U.S. Senator Robert Kennedy, who was assassinated during his 1968 presidential bid.

In April, Kennedy said he would challenge Biden to run for the Democratic nomination against the expected Republican nominee, former President Donald Trump.

Since then, Kennedy has complained that the Democratic Party has “basically blended together” with the Biden campaign, which has cost him a fair chance in the nomination race.

Many polls have Biden ahead of Kennedy.

Kennedy’s plan to run as an independent was first reported on the political website Mediaite.

In response to an emailed question from Reuters about the report, the Kennedy campaign responded by sending out its own video.

Democrats worried that any effort by a third party could shift votes away from Biden.