The U.S. regulator that exposed German automaker Volkswagen's cheating on emissions testing is expanding its investigations into the sector and will scrutinize diesel vehicles produced by BWM, Chrysler, General Motors, Land Rover and Mercedes-Benz, to see if other manufacturers were engaged in similar deceptive practices.

Volkswagen used a software known as a “defeat device,” on at least 11 million of its diesel vehicles worldwide. The device restricted the amount of pollution the vehicle would emit only while it was being tested. Outside of the test environment, vehicles would emit up to 40 times the amount of pollution permitted under U.S. regulations.

According to the Financial Times, which first reported the news, the Environmental Protection Agency's expanded probe will see it investigate 28 diesel vehicles on sale in the U.S. The agency will test one of each of the models under investigation, and then widen its investigation if it finds anything suspicious, a senior agency official told the paper.

The vehicles that will come under scrutiny include BMW's X3, Chrysler's Grand Cherokee, GM's Chevrolet Colorado, the Range Rover TDV6 and the Mercedes-Benz E250 BlueTec.

The Volkswagen scandal has prompted the EPA to toughen and broaden emissions tests for all automakers in an effort to thwart any other cheating activities, a move that could add to industry costs and higher regulatory hurdles, Reuters reported.

The embattled German automaker is facing a raft of regulatory action, as well as class-action lawsuits across the U.S. and in Europe. California authorities have announced that a “major” enforcement action against the company is pending, and other U.S. states have announced investigations. In Europe, Germany, France and Italy have opened investigations into the scandal.

Volkswagen has also halted the sale of some diesel cars in countries, including the U.S., the U.K., Holland and Australia. The halts to sales in some countries began after it emerged that the company had continued to sell cars equipped with the defeat devices in Europe, after the scandal had been uncovered in the U.S., the Guardian reported.

The company faces up to $18 billion in fines over the scandal.