Rolling Stones guitarist Ronnie Wood says his pregnant wife has left Brazil to avoid exposure to the Zika virus.

In a message posted on Twitter Monday, the musician says that Sally Wood had decided to leave the band's tour of Latin America because the Zika virus and excessive flying was "too dangerous" for their unborn twins.

The Rolling Stones played the first Brazilian gig of their "Ole Tour" at Rio de Janeiro's Maracana stadium on Saturday night. Next they head to Sao Paulo, then Porto Alegre, before travelling to Peru, Colombia and Mexico.

On Sunday, the couple both announced on Twitter that they were expecting girls. Media reports say the babies are to be born in June.

Ronnie told fans, "Our baby girls are growing beautifully. Thank you for the love!"

On Feb. 1, the World Health Organization declared the mosquito-borne Zika virus outbreak in the Americas a public health emergency.

WHO director general Dr. Margaret Chan said the potential link between Zika virus and clusters of babies with microcephaly — an unusually small head that is associated with incomplete brain development — warranted the declaration.

But WHO officials say it could be six to nine months before science proves or disproves any connection between Zika and the spike in the number of babies born in Brazil with abnormally small heads.