Organizers of the Formula One World Championship announced Friday that planned races in Singapore, Japan and Azerbaijan have been canceled for 2020 due to complications caused by the ongoing Covid-19 coronavirus pandemic.

They join the Australian, Dutch, French and Monaco Grands Prix which have also been canceled for 2020.

The organizers, which include F1 management, the FIA, and the teams, are working on a revised calendar and plan to announce it before the delayed state of the 2020 season in early July. They're hopeful of hosting between 15 and 18 races, but due to scheduling issues some of the traditional races need to be replaced or canceled.

In the case of the Japanese Grand Prix, originally scheduled for October, the organizers said ongoing travel restrictions make it impossible to include the race. As for the Singapore and Azerbaijan Grands Prix, originally scheduled for September and June, respectively, the long lead times required to build their street circuits and the uncertainty surrounding travel restrictions also make it impossible to include them.

The 2020 calendar was set to host a record 22 races, including new rounds in the Netherlands and Vietnam, but then the coronavirus came and threw a spanner in the works. The organizers last week confirmed the first eight races of the revised 2020 calendar, which include back-to-back races in Austria and the United Kingdom. The first race of the revised calendar will be the Austrian Grand Prix in Spielberg, Austria, on July 5.