The inaugural Korean Grand Prix could be called off, according to a report in the German media.
The news magazine Focus says the circuit under construction in Yeongam, about 400 kilometres south of the capital Seoul, may not be completed by the time of its scheduled debut race this year at the end of October.
Amid rumours of serious problems with the construction, the report said F1 chief executive Bernie Ecclestone travelled directly to South Korea after last Sunday's Malaysian Grand Prix.
The report said the 79-year-old will decide in the coming days whether or not to cancel the race, which would reduce the 2010 schedule from a record-equalling 19 events to 18.
F1 regular Hermann Tilke's company was responsible for the design of the circuit, but unlike most of his other projects, the German architect is only an advisor for the actual construction in Korea.
"For the first time I am concerned that a (Tilke) circuit is not going to be finished on time," he is quoted as saying.
Focus said a possible outcome for South Korea, despite tickets for the October 24 race already being on sale, is a postponement for one year.