The singer Morrissey is being treated for "physical exhaustion" after cancelling a string of concerts.
He has also been told to rest for two weeks, his tour manager said.
The former Smiths frontman had been due to play at the Honda Centre in Anaheim, California, on Friday, and at the Kia Forum in Los Angeles on Saturday.
Both venues said on social media that the gigs had been cancelled "due to unforeseen circumstances".
They were going to celebrate the 20th anniversary of his solo album You Are The Quarry.
The singer, 64, is on a tour called "40 years of Morrissey" - but gigs for the next month, scheduled for countries including Peru, Chile and Argentina, appear to be off too.
According to the website Morrissey-Solo, concerts in south America, until 24 February, had been cancelled.
Tour manager Donnie Knutson wrote on Instagram that Morrissey is "receiving medical supervision for physical exhaustion".
Knutson added: "He has been ordered to rest for two weeks, and he will remain in Zurich."
The Smiths' first album, called The Smiths, was released on 20 February 1984, and featured songs including Hand in Glove and What Difference Does It Make?