Two U.S. senators sent a letter Tuesday to embattled parts supplier Takata Corp., pressing the company to voluntarily recall all vehicles in the country installed with its air bags. The move follows a revelation this week that U.S. regulators are investigating an air bag rupture in a newer model car.

"In light of the most recent incident, which did not occur in one of the regions originally designated as 'high humidity,' and which involved a 2015 vehicle not currently subject to recall, we urge you to voluntarily recall all vehicles containing Takata air bags," Richard Blumenthal and Edward Markey wrote in the letter addressed to Takata's U.S. arm.

The National Highway Traffic Safety Administration opened a probe into a June accident in which a Takata side air bag in a Volkswagen Group sports utility vehicle exploded, U.S. media recently reported. While no one was hurt, it was the first such incident for the German automaker and the first known rupture of a side air bag.