The Czech Republic insist they've followed all coronavirus guidelines, after members of the squad were forced to self-isolate.
The central European nation face Scotland in the Nations League next week, but their preparations have been thrown into disarray.
West Ham midfielder Thomas Soucek and RB Leipzig striker Patrik Schick are in quarantine after testing positive for COVID-19.
As a result Czech champions Slavia Prague have threatened to pull all their players out of the squad, but the national team insist they did nothing wrong.
A statement said: "The Czech national football team strongly opposes the accusation that it violated any regulations or underestimated anything during the ongoing camp.
"The national team strictly adheres to UEFA 's rules, which it has also tightened on several points to minimise the risk of Covid-19.
"Without UEFA ordering this, all members of the national team and other people were tested with a negative result before the start of the event.
"At the same time, the whole team has clearly set rules of conduct in hotels and stadiums. The football association has invested significant financial, time and personnel resources in these measures.
"The Czech national football team regrets the positive test of one of its members and the preventive placement of two players in quarantine, despite the negative test results.
"We will fight for them in the match against Slovakia. At the same time, we consider it essential that everyone else has negative test results and is ready for the match."
