Honda Motor Co. has begun an investigative recall in Okinawa over air bags made by Takata Corp., the first such move in Japan, a company official said Monday.

The Japanese carmaker is calling back 635 vehicles in the prefecture, without identifying the cause of possible defects in the air bags' inflators, which could explode too forcefully, releasing metal fragments into cars.

Given a shortage of replacement parts, Honda has initially launched the recall in hot and humid regions before expanding it to other parts of the country, as it has done in the United States.

The total number of cars subject to the recall stands at around 135,000 across Japan.

Major carmakers have recalled more than 20 million cars around the world over the Japanese supplier's air bags, which have been linked to several deaths in the United States and Malaysia.

Mazda Motor Corp., meanwhile, informed the transport ministry that it will start its investigative recall in Japan next month covering 38,083 vehicles with Takata air bags.

The figure is lower than Mazda's earlier estimate of 52,000 as some of the vehicles have already been scrapped, the company said.

The recall affects RX-8 sports cars produced between January 2004 and February 2008, and Atenza sedans made between January 2004 and May 2005.