Formula One fears that further COVID-19 lockdowns across Europe could hit the sport as Lewis Hamilton heads towards a record-equalling seventh world title, his Mercedes team boss Toto Wolff said.
Speaking ahead of this weekend's Emilia Romagna Grand Prix, the third race to be held in Italy in an extraordinary coronavirus-affected season, Wolff said developments were worrying.
"The situation is becoming more difficult," he said at the Autodromo Enzo e Dino Ferrari on Friday. "F1 does not put anyone in danger as we stay in our microcosm, but we also cannot ignore that the number of cases in various countries is growing rapidly.
"At some point, the leaders of these countries may decide to close the borders which may affect our plans."
Wolff was also concerned about F1's provisional plans for an unprecedented 23-race season next year.
"As of now, Chase Carey (F1 chief executive) has assured us that the schedule remains in place," he said. "But he also said that, against the backdrop of a progressing pandemic, no one knows what the situation will be in a week — let alone a month."