(CNN) -- Linkin Park canceled its Thursday night show in Washington, D.C., after the group's lead singer fell ill, the band said on its website. "Lead vocalist Chester Bennington is ill and under doctor's orders to refrain from performing," the statement said. "The band sincerely regrets this unavoidable cancellation and apologizes to fans for any disappointment caused." The California sextet is on tour to promote its latest release, "A Thousand Suns." The band's website says Linkin Park's next scheduled show is Friday in Uncasville, Connecticut, at the Mohegan Sun Resort and Casino. The Recording Industry Association of America (RIAA) says the alternative metal band has sold more than 19 million units -- a combination of CDs and digital downloads.
Linkin Park music sales top 19 million units . The band is on tour to promote its latest release, "A Thousand Suns" Linkin Park's next scheduled show is Friday in Uncasville, Connecticut .