A Democratic political group that has run ads questioning presidential candidate Bernie Sanders’ electability—and his health—is now going after Sanders in Nevada.

The Democratic Majority for Israel PAC has purchased tens of thousands of dollars in cable and network ad time this week ahead of the Feb. 22 presidential nominating caucuses, according to documentation filed with the Federal Communications Commission. The ads are scheduled to run for a week starting on Saturday.

The precise size of DMFI’s Nevada purchase was not immediately clear; the group had not yet filed an independent expenditure report with the Federal Election Commission as of Friday morning. But FCC filings indicate the total size of the buy is more than $175,000.

DMFI also ran anti-Sanders ads in the run-up to the Iowa caucuses earlier this month. Its thirty-second video spot questions Sanders’ ability to prevail in a general election contest and even raises concerns about the Vermont senator’s health.

“I do have some concerns about Bernie Sanders’ health, considering he did have a heart attack,” a woman featured in the ad says.

Mark Mellman, a Democratic consultant who runs DMFI PAC, said the group’s ad in Nevada would be different from the one that ran in Iowa, but did not provide further details.

The group has received the bulk of its funding from a handful of high-dollar donors. Stacy Schusterman, a Tulsa oil and gas heiress, gave DMFI PAC nearly $1 million in December, according to FEC records. The group got another $495,000 from venture capitalist Mark Gary Lauder.

DMFI’s new broadside against Sanders comes as he tries to squeak ahead in the race for Democratic delegates in the party’s third presidential nominating contest. He trails former South Bend mayor Pete Buttigieg by a pair of delegates despite strong showings in both Iowa and New Hampshire.

DMFI’s plans for a Nevada offensive against Sanders were first reported by Mediaite. FCC filings posted on the agency’s website on Wednesday and Thursday show DMFI has purchased ad time on broadcast stations in Las Vegas and Reno, as well as a host of statewide cable programs.