"His remarks on race are offensive, and I wholeheartedly disagree with him," Paul said.
Heller, who last week called Bundy defenders "patriots" for their stand against the government, "completely disagrees with Mr. Bundy's appalling and racist statements, and condemns them in the most strenuous way," said his spokeswoman, Chandler Smith.
Senate Majority Leader Harry Reid, a Democrat who last week called Bundy supporters "domestic terrorists," also spoke out against Bundy's words.
"Today, Bundy revealed himself to be a hateful racist," Reid said. "But by denigrating people who work hard and play by the rules while he mooches off public land, he also revealed himself to be a hypocrite."
Bundy says he doesn't recognize federal authority over lands around his property that his cattle have grazed on for years.
The Bureau of Land Management claims the cattle are trespassing on fragile Gold Butte habitat set aside for the endangered desert tortoise, and that Bundy has racked up some $1.1 million in fees and penalties since 1993.
Supporters rushed to Bundy's ranch after a YouTube video showed federal agents using a stun gun on Bundy's son during a BLM roundup of the family's cattle. The resulting armed standoff became so tense that BLM agents and contractors called off the weeklong roundup, released about 350 animals back to Bundy and left the area April 12.
Federal officials have said the agency would pursue unspecified administrative and judicial remedies, but BLM officials have not provided details.