SAO PAULO -- Brazil is testing an experimental COVID-19 vaccine, but interim Health Minister Eduardo Pazuello acknowledged on Tuesday that his government has yet to strike a deal to get it if it works. Other nations have already secured hundreds of millions of doses of the shot created by Oxford University.

The country's coronavirus response has faced criticism since March, when President Jair Bolsonaro started defying social distancing recommendations. Hours before Brazil's health minister spoke at congress, a judge ordered Bolsonaro to wear a face mask whenever he is outdoors in the capital of Brasilia.

Pazuello, an army general who made his career in logistics, discussed Brazil's efforts to buy a vaccine for COVID-19 or acquire the technology to make it. The country's health regulator Anvisa approved human clinical trials for the potential vaccine this month.

Pazuello said a decision on a deal for Brazil to acquire the planned vaccine is expected by the end of the week, but will depend on the government's chief of staff.

British researchers started testing the experimental shot in May aiming to immunize more than 10,000 people, including older people and children. The vaccine created at Oxford is one of about a dozen in early stages of human testing.

Brazil, where the pandemic is still on the rise, is the only country other than the United Kingdom testing that vaccine. The country counts more than 1 million confirmed COVID-19 cases and almost 52,000 fatalities.

Clinical trials began in Sao Paulo on Monday and will start in Rio de Janeiro on Wednesday. The British embassy in Brazil says 5,000 health professionals are being vaccinated.

"We are working directly with the three most promising (vaccines)," Pazuello said, naming the Oxford shot, the vaccine under development by American company Moderna and one of the Chinese experiments, which he did not disclose.

Bolsonaro has been criticized for downplaying his government's response to the pandemic, comparing the disease to "a little flu."

On May 21, the United States announced a deal for at least 300 million doses of the Oxford shot, and committed up to $1.2 billion to the effort. On June 13, pharmaceutical company AstraZeneca agreed to supply up to 400 million doses of the experimental vaccine to European Union nations. Other negotiations are ongoing with Russia and Japan, among other countries, the company's CEO said this month.

Another experimental vaccine in development by Chinese company Sinovac Biotech will be tested in Brazil in July, according to the Sao Paulo state government. Sinovac has a deal with the state's Instituto Butantan to produce it. Some 9,000 Brazilians are expected to participate.

Earlier Tuesday, a Brazilian federal judge ordered Bolsonaro to comply with local rules to wear a face mask or be fined.

In recent weekends, a sometimes unmasked Bolsonaro has joined throngs of people protesting against Brazil's Congress and Supreme Court and he has visited bakeries and outdoor food stalls, drawing crowds around him.

Since the end of April, Brazil's federal district has required people to wear face masks in public to help control the spread of the new coronavirus. Failure to comply carries a possible daily fine of $390.

Judge Renato Coelho Borelli said in his ruling that Bolsonaro "has exposed other people to the contagion of a disease that has caused national commotion."

The Brazilian president did not immediately comment on the decision. An earlier court ruling required him to publish the results of three COVID-19 tests he took early March, and all were negative for the virus. He has not disclosed any tests since then.

Bolsonaro sometimes appears in public events with a mask, unlike some other heads of state, including U.S. President Donald Trump, Mexico's Andres Manuel Lopez Obrador and Argentina's Alberto Fernandez, who has often hugged supporters and taken selfies with them while not wearing a mask, although use of a mask is mandatory in Argentina's capital.

Associated Press writer Mayra Pertossi contributed from Buenos Aires, Argentina.