Rohit Sharma, Rishabh Pant, Shubman Gill, Prithvi Shaw and Navdeep Saini have been placed in isolation as a precaution pending investigation into a video posted on Twitter that purportedly showed the group eating in an indoor restaurant in Melbourne. The players will be allowed to continue training but not with the rest of the group.

The statement released by Cricket Australia said the action was taken in consultation with both the boards' medical units but didn't expressly state if it was a breach of biosecurity protocols to eat at an indoor venue outside the team hotel. Nor did it say what the course of action will be if it is indeed a breach of protocols.

A Twitter post by a fan of Indian origin claimed he had spotted the five India players eating at the same restaurant as him. He said he had paid for the cricketers' food unbeknownst to them. An initial tweet claimed that Pant hugged the fan when he found out that the food had been paid for, but that tweet was retracted later, with the fan stating that Pant never hugged him, and that he had gotten carried away in excitement when tweeting previously.

"In the interim, on the advice of the Australian and Indian medical teams, the aforementioned players have been placed in isolation as a precaution," the release said. "This will include separating the group of players from the broader Indian and Australian squads when traveling and at the training venue.

"Players will be permitted to train in accordance with the strict protocols that have been put in place to ensure the ongoing safety of all members of the Indian and Australian squads. Similar measures were taken during the BBL this season after it was determined two Brisbane Heat players failed to comply with tournament biosecurity protocols."

It is not yet clear if India agreed to the same protocols, but Australia players are required to eat only at outdoor venues in public places. The teams have been training in Melbourne even though the next Test is scheduled to be in Sydney. While CA is confident the Sydney Test will go ahead as scheduled, a last-minute change of venue owing to the recent Covid-19 outbreak and the consequent closing of borders between New South Wales and other states cannot be ruled out.

Sharma had joined the Indian team in Melbourne the day after India finished their series-levelling victory at the MCG. He was named the team's vice-captain upon joining the squad, which might have been indication he is in line to make his Test comeback after last playing more than a year ago. He missed the limited-overs leg of the tour with a hamstring injury and then the start of the Test series because he had to be in hard quarantine upon arriving in Australia.

Victoria recently ended two months with no community transmission of Covid-19, with the cases linked back to the outbreak in the northern beaches area of Sydney which has now spread to further parts of the city. For a time, the outbreak appeared to have put the SCG Test at risk. But the plans are for the game to go ahead as scheduled from January 7 with the teams - and a small group of broadcast and technical personnel - having been granted exemptions to travel to Brisbane for the final Test. Queensland's borders are currently closed to Greater Sydney due to the outbreak.

There has been no communication from the BCCI.