Both major Japanese airlines plan to cut capacity significantly on their China routes due to a wave of cancellations prompted by a political dispute between the two nations.

All Nippon Airways confirms that it will be temporarily reducing capacity on its three key routes to Beijing. This will be done by downgauging aircraft size on these flights, an airline spokeswoman tells AviationWeek. Last week, JAL announced it would be suspending three of its daily flights to Beijing and Shanghai.

The major cause of the service reductions is Chinese travelers canceling flights to Japan, although Japanese travelers are also changing their plans. Tensions between Japan and China have risen in recent weeks due to a dispute over sovereignty of a group of tiny islands in the East China Sea.

ANA has not yet canceled any flights, the airline spokeswoman says. But it has put Boeing 737s on its flights from both Tokyo Narita International Airport and Osaka Kansai International Airport to Beijing, instead of the usual 767s. It has also put a 767 on its Tokyo Haneda-Beijing route, instead of a 777-200. This downgauging applies for different periods on each route, ranging from seven to 13 days, all during the second half of October.

ANA passengers have canceled bookings for 37,000 seats during the three-month period from September to November, out of a total available 880,000 seats in the Japan-China market for that period.

JAL, meanwhile, will suspend one of its two daily flights between Tokyo Narita and Beijing, one of its three daily Narita-Shanghai services, and one of its two Kansai-Shanghai flights. The cuts will all apply from Oct. 10-27. The carrier’s winter schedule begins Oct. 28, and it says it will notify travelers if there are further changes after that date.

A JAL spokeswoman tells AviationWeek that travelers have canceled 14,600 one-way seats during the three months from September to November. About 6,600 of the cancelations were by outbound travelers from Japan, with 8,000 by travelers from Japan. Most of these are leisure rather than business passengers, the spokeswoman says.