The Aug. 11, 2009, file photo shows Thomas Steg during a news conference in Berlin. Volkswagen suspended Steg, the head of external relations, in connection with scandal over use of monkeys in research the company said Tuesday, Jan. 30, 2018. (AP Photo/Markus Schreiber, file)

FRANKFURT, Germany (AP) — Automaker Volkswagen has suspended a top executive in response to widespread public criticism over experiments in which monkeys were exposed to diesel exhaust.

The company said in a statement Tuesday that Thomas Steg, head of government relations and sustainability, was stepping away from his duties at his own request.

The statement said the company was "drawing the first consequences" as it investigates the activities of EUGT, the entity backed by Volkswagen and other carmakers that commissioned the monkey experiment.

Steg had said in an interview published in the newspaper Bild that he had known about the experiment but did not inform the company's then-CEO, Martin Winterkorn. Steg said he rejected an initial proposal to use human volunteers and said that even after animals were substituted the experiment "should not have taken place."

The move follows a report in The New York Times that the now-disbanded EUGT commissioned the 2014 monkey test at the Lovelace Respiratory Institute in Albuquerque, New Mexico, to measure how Volkswagen's diesel technology was succeeding in controlling harmful emissions.

Diluted exhaust gases from a late-model Volkswagen vehicle were fed into chambers where the monkeys were exposed for four hours. Afterward, lung fluid samples were taken from the sedated monkeys, which were not killed for the experiment. The study did not deliver a definitive result.

The test was done with a vehicle that used illegal software to cheat on emissions tests, turning controls off when the vehicle was not being tested. That practice was exposed in 2015, leading to Winterkorn's resignation.

The Lovelace Respiratory Research Institute said in a statement that the tests were designed by EUGT and the lab itself was initially not aware the vehicle had been rigged. It said it complied with regulations for the treatment of lab animals and was committed to their humane and ethical treatment.

The labs president and CEO, Robert W. Rubin, said in a statement that when the lab later learned that the vehicle engine had been modified to produce less pollution "we determined the study was compromised" and did not meet the standards for publication.

"We understood that the EUGT organization was financially supported by automobile manufacturers, but we believed the goal of the study was to advance the scientific understanding of the effects of diesel fumes on our lungs, including the effects of new vehicle technologies that are designed to produce less pollution," he said.

Volkswagen's current CEO, Matthias Mueller, said in the VW statement that "we are investigating in detail the work of EUGT, which was dissolved in 2017, and drawing the necessary conclusions." He said Steg "has declared that he takes full responsibility, and I respect that."

Volkswagen said the probe would be carried out "at top speed." Board Chairman Hans Dieter Poetsch said the board's executive committee expected to hear the status of the investigation next week, the dpa news agency reported.

"We will ensure that such things will not be repeated," he said. The company has said that rejects animal experiments and that "we apologize for the wrong behavior and bad decisions of individuals."

Government officials, environmental groups and animal rights activists all condemned the experiment.

Daimler and BMW also condemned the experiment and said they were investigating. The New York Times report said the three companies backed EUGT financially.

The monkey scandal is another black eye for the German auto industry as it seeks to move past the Volkswagen scandal and the doubts it unleashed over how clean diesel technology really was.

Volkswagen paid billions in fines and settlements and pleaded guilty to criminal charges. The Volkswagen case led to increased scrutiny of diesel cars from other manufacturers, which were found to emit more in everyday driving than during tests, though not necessarily through illegal software as at Volkswagen.