Spain have called up five players to take part in a parallel training bubble following captain Sergio Busquets's positive Covid-19 test, the team said on Monday.
Spain later confirmed that the other squad members and backroom staff had all tested negative and trained individually earlier in the day.
The additions - Rodrigo Moreno (Leeds United), Pablo Fornals (West Ham United), Carlos Soler (Valencia), Brais Mendez (Celta Vigo) and Raul Albiol (Villarreal) - will not stay at Spain's Las Rozas training base or be involved with the rest of the squad.
"As a provision to the possible consequences that could come from Sergio Busquets's positive test, the coaching staff have decided to call up a group of four players to complement the training sessions over the next few days under the guidance of (manager) Luis Enrique in a parallel bubble," Spain said in a statement.
Spain are due to face Lithuania in a friendly on Tuesday with their Under-21 squad, who have just finished playing in their own European Championship where they reached the semi-finals, and coach Luis de la Fuente stepping in to fill the gap left by the isolating senior set-up.
"Once the game with Lithuania has finished, a small group of players yet to be determined will join training in a similar fashion to the aforementioned new group.
"Their incorporation into the squad for Euro 2020 will depend on the results that come back over the next few days."
Spain play Sweden in their Group E opener next Monday.