Some players and staff at top football clubs in Spain, Italy and the UK tested positive for COVID-19, reports said on Monday, although elite sport was set to continue in England despite new lockdown measures. 

Brazilian defender Alex Sandro of Juventus has gone into isolation, the Italian champions said on Monday. The 29-year-old played in Sunday's 4-1 home win over Udinese Calcio in Serie A. 

"Juventus Football Club announces that, following the appearance of some mild symptoms, a check was arranged for the player Alex Sandro, which revealed that he is positive with COVID-19," a club statement read.

"The club is in contact with the Health Authorities to define an effective implementation of the protocols required to allow for the training and competition activities of the team."

Two members of Barcelona's first team staff also tested positive for COVID-19, the Catalans said. 

A statement said the whole squad would undergo tests on Tuesday, in line with La Liga's protocol.

They added that their training session and news conference ahead of Wednesday's La Liga match against Athletic Bilbao would be rescheduled.

Manchester City said four players of its women's team were now self-isolating after testing positive. City did not name the players.

The club has battled a COVID-19 outbreak in the men's squad in the past two weeks, with six players testing positive. Their Premier League match at Everton was postponed and the training ground closed for two days as a precaution.

Elite sport however will be allowed to continue in England despite British Prime Minister Boris Johnson announcing a new national COVID-19 lockdown on Monday due to surging infections in the country caused by a more contagious variant of the coronavirus.

Outdoor sport venues including outdoor gyms, tennis courts and golf courses will close and outside team sports will not be permitted but elite sport, including Premier League football, will continue.

The Premier League recorded a season-high 18 positive cases in a week last month and a total of 131 individuals in the English top flight have tested positive in 17 rounds of testing.

However, unlike the Premier League, cancelled Premiership rugby matches will not be replayed, with four points allocated to the team who were able to play the game and two points to the other club.