Former Vice President Joe Biden will spend $6 million to run digital and TV commercials in the early-voting primary and caucus states, his campaign said Thursday, as he attempts to keep pace with Sen. Elizabeth Warren, currently his main rival for the Democratic presidential nomination.

Biden’s campaign announced that it's reserving “prime advertising space on traditional television and on digital platforms like YouTube, Hulu and news and sports streaming services” in Iowa, New Hampshire, Nevada, and South Carolina, the first four states on the presidential nominating calendar.

WARREN SHOWCASES $10 MILLION AD BUY IN EARLY VOTING STATES

The move comes a week after Warren’s campaign said it would dish out at least $10 million to run digital and TV spots in the same four crucial states.

Warren and Biden are virtually tied for the top spot in most recent national and early-voting-state polls.

While the Biden campaign is already running digital ads across the country and has spent six figures to run TV commercials in Iowa, this is its first major multi-state ad buy.

“We’ve been up on the airwaves in Iowa and blown away by the reaction we’ve seen to Vice President Biden’s deeply personal ad about health care,” Biden campaign manager Greg Schultz said in a statement.

THE LATEST FROM FOX NEWS ON THE 2020 PRESIDENTIAL CAMPAIGN

Sen. Bernie Sanders’ campaign announced earlier this week that it would go up Thursday with the first TV commercial of the Vermont senator’s 2020 White House bid. But the campaign said on Wednesday – after confirming that Sanders was taking time off from the campaign trail following a heart procedure -- that the $1.3 million ad buy in Iowa was being postponed.