The National Highway Traffic Safety Administration prompted the recall, the Los Angeles Times reported.
The recall involves model year 2010 Lexus RX 350 and RX 450 H vehicles.
The NHTSA said the problem was "a serious safety issue involving potential pedal entrapment by the floor mat."
In a statement that is also reminiscent of Toyota's 2009 recall of 4.4 million vehicles, the NHTSA said it was investigating whether or not Toyota had acted "in a timely manner" regarding its obligation to notify regulators of a safety concern.
The 2009 recall involved 14 Toyota models, but not the Lexus sports utility vehicles.
"In our view, the data available at the time didn't warrant the inclusion of this model. If NHTSA decides to open an investigation, we'll certainly cooperate with its efforts," said Toyota spokesman Brian Lyons.