Japanese MotoGP team Yamaha have withdrawn from the Qatar Grand Prix because of the ongoing conflict in the Middle East.

The event at the Lusail International Circuit is set to take place on 6-8 November, having been postponed from April.

MotoGP is going ahead with the race, despite reports 19 of 22 riders have signed a letter raising concerns about competing in Qatar during the US-Israeli war on Iran.

In February, the United States and Israel launched air strikes against Iran, which in return fired missiles at Israel, and at other countries in the region with links to the US.

Yamaha said it has "not identified sufficient grounds to change its existing company-wide travel restrictions" on travelling to the Middle East, with the Japanese government advising its citizens against non-essential travel to the region.

MotoGP said it is "disappointed" by Yamaha's decision, which it says does not reflect the "extensive assurances" it has been given by Qatar and independent safety advisors that the race can go ahead.

Qatar has said it can guarantee teams would not be stranded in case of any escalation in the conflict.

How Israel resolves its political deadlock following recent elections and the results of Tuesday's US midterms could have significant impacts on the situation in the Middle East.

MotoGP added there will be "sporting implications" for Yamaha's withdrawal. Fellow Japanese outfit Honda and Yamaha's satellite team Pramac Racing are currently set to compete in Qatar.

MotoGP is organised by Liberty Media, which also own Formula 1.

The F1 season is currently set to culminate in the Qatar GP from 27-29 November, followed by the Abu Dhabi GP on 4-6 December.

F1 is continuing with plans to stage both races, having been given what it considers suitable security guarantees and reassurances, despite it this causing some disquiet in the paddock.

F1 is being advised there have been no attacks on civilian infrastructure in Qatar or the United Arab Emirates since May.

Imola in Italy is being readied as a potential host for the final grand prix of the season on 4-6 December if the two races in Qatar and Abu Dhabi cannot be held.