England players Ben Chilwell and Mason Mount are self-isolating after coming into contact with Scotland midfielder Billy Gilmour, who tested positive for COVID-19 earlier on Monday, putting them both in doubt for Tuesday's game with the Czech Republic.
"The pair will be kept away from the rest of the England players and wider support team," the Football Association said in a statement.
England manager Gareth Southgate said it was not yet clear if the two would be available for England's final Group D match against Czech Republic at Wembley on Tuesday night.
"We don’t know at the moment. There has obviously got to be quite a doubt. There are still a lot of discussions and investigations going on behind the scenes… We just have to find out over the next 12 hours or so," he told a news conference.
Current UK regulations for people who have been informed that they have come into contact with someone who has tested positive are for them to isolate for 10 days.
Midfielder Mount has started both England's games while left-back Chilwell has yet to feature.
Both players are team mates of Gilmour's at Premier League club Chelsea and were pictured embracing him at the end of Friday's 0-0 draw at Wembley.
The FA said the move was a "precaution at this time" and the decision had been made after consultation with Public Health England (PHE).
"The entire squad had lateral flow tests on Monday afternoon and all were again negative, as was the case with Sunday’s UEFA pre-match PCR tests".
Southgate said he did not know if the situation came about because of contact from PHE or if the contact with Gilmour had been reported to them.
None of the Scotland team, who have all since tested negative, have had to isolate after being in contact with Gilmour, and Southgate appeared puzzled at the different approaches.
"I don't want to cause a drama for Scotland, but if you're all in the dressing room together, where does everything stand?" said Southgate.
"I don’t know all of the factors behind that but clearly it’s nothing to do with being on the pitch," he said, noting that it was acknowledged that there is not enough close contact time on a field during training or a game to count as being exposed.
Southgate added that he had sympathy for Scotland coach Steve Clarke and when asked if the players had been vaccinated, which they have not, offered a reminder that he had proposed such a move.
"In terms of the vaccinations, you need to go back to my suggestions in March around that where I was fairly firmly shouted down for daring to suggest anything of the sort," he said.
"I did propose it but at the time I also said I totally understood where we stand in the pecking order for vaccinations.
"In actual fact the vaccinations wouldn't stop you catching the virus so it might not necessarily have stopped this situation in fairness," he added.