Formula One decided to pack five European races into six weeks on its 2018 calendar because organizers wanted to avoid a clash with the World Cup Finals in Russia, chairman Chase Carey said Tuesday. The 21-race calendar was published by the governing International Automobile Federation (FIA) Monday with Grands Prix in France, Austria and Britain taking place on successive weekends on June 24, July 1 and 8. Races in Germany and Hungary will also be held on July 22 and 29. The 2018 World Cup final will take place at Moscow's Luzhniki Stadium on July 15. "Every year there is always a unique thing we're playing around and next year it has got this unique event, the World Cup final," Carey said at an FIA Sport Conference in Geneva. "So part of the schedule of having three (races) in a row was because we did not think it was ideal for a promoter to have an event (go) head-to-head with the World Cup final." Carey said Formula One management had discussed the situation with promoters before deciding to hold the unprecedented triple-header. "We made sure with our partners that it was manageable," he added. "I think everybody thought that was manageable and within that schedule (we) did preserve the four-week break in August." The 2018 calendar has one more race than this year's due to the return of France, after a 10-year absence, and Germany while Malaysia departs. China and Singapore were both listed with asterisks against them, as subject to confirmation with the commercial rights holder, but Carey said there was no concern about those races not happening. He also did not expect the draft calendar to change, as was the case in past years when former supremo Bernie Ecclestone drew it up. "It's just the reality of having agreements that have come up. We're negotiating new agreements, we're having good, constructive discussions, and expect to get there," Carey said of the two Asian races. "We don't expect it to be 19, we expect it to be 21. We wouldn't have put it out if we didn't expect it to be 21, but the reality is we don't have a completed agreement." The race at Le Castellet, inland from Marseille, will be on June 24, avoiding a clash with the Le Mans 24 Hours on June 16-17, followed by Austria on July 1 and Silverstone on July 8. Formula One has not had three races on successive weekends before, due to logistical reasons, although it has been mooted. A proposed street race in New Jersey was sandwiched between Monaco and Canada on the provisional 2014 calendar but the US round did not happen for financial reasons. The season will start in Australia on March 25 with teams then travelling to Shanghai and Bahrain, which will be back-to-back on April 8 and 15, before the Azerbaijan Grand Prix on April 29. Russia was the fourth round this year but that race moves away from the May Day holiday weekend to an end of September slot instead. Spain's Circuit de Barcelona opens the European season on May 13, followed by the showcase Monaco race, before Formula One travels across the Atlantic to Canada on June 10 and then returns to France. Germany returns on July 22 with a race at Hockenheim, followed by Hungary on the next weekend, with the three-week August break maintained after fears it might have to go to accommodate the extra races. Belgium's Spa-Francorchamps and Italy's Monza are also back-to-back races, in late August and early September, with Singapore — Asia's glittering floodlit night race — a stand-alone on Sept 16. Russia and Japan are paired, as are the US Grand Prix in Austin, Texas, and Mexico. The season ends in Abu Dhabi, as usual, on Nov. 25. Liberty wants ultimately to increase the number of races in the United States and there has been talk of the calendar stretching to as many as 25 rounds after 2018. — Agencies