Rio de Janeiro: Brazilian President Jair Bolsonaro asked Indian Prime Minister Narendra Modi to expedite a shipment of AstraZeneca's COVID-19 vaccine amid broader delays to the vaccine's arrival in Brazil, according to a letter on Friday.

Bolsonaro's letter, released by his press office, comes amid growing pressure to speed up Brazil's vaccine rollout and end the world's second-deadliest coronavirus outbreak. Critics say the immunization campaign is running behind regional peers, and they question why the government has not moved more quickly.

"To enable the immediate implementation of our National Immunization Program, I would appreciate ... the supply to Brazil, with the possible urgency and without jeopardizing the Indian vaccination program, of 2 million doses," Bolsonaro wrote in the letter, shared by his press office.

His message to Modi comes as the federally funded Fiocruz biomedical centre said on Friday that the active ingredients needed to fill and finish millions of doses of AstraZeneca's coronavirus vaccine in Brazil, previously slated to arrive in the country on Saturday, may not land until the end of the month.

Fiocruz, which was counting on the shipment Saturday to supply the government with doses this month, said it was in talks to import more finished doses of the vaccine, likely from India on top of the 2 million it has already ordered.

A source involved said the active ingredient is ready to be shipped to Brazil but is waiting for an export license from China, where it is produced.

Earlier, Fiocruz requested an emergency use authorization for AstraZeneca vaccines coming from India, which are expected to arrive in Brazil in the middle of this month.