4:39 AM ET

American sprinter Justin Gatlin has denied using performance-enhancing drugs after an undercover report by The Telegraph in London into alleged activities by Gatlin's representatives led to the opening of a doping investigation.

"I am not using and have not used PED's," Gatlin, the world champion in the 100 meters, wrote in a statement posted Tuesday to Instagram.

A post shared by justingatlin (@justingatlin) on

The United States Anti-Doping Agency and the Athletics Integrity Unit for the International Association of Athletics Federation on Monday opened an investigation into Gatlin, his coach Dennis Mitchell, and Robert Wagner, an agent who has worked for Gatlin.

"Investigations from tips and whistleblowers play a critical role in anti-doping efforts," a USADA spokesperson told The Telegraph. "We are presently coordinating with the Athletics Integrity Unit in order to investigate these claims fully."

Renaldo Nehemiah, Gatlin's agent, told the publication that Wagner had only worked for Gatlin on two or three occasions. Nehemiah also said Gatlin was not present for any discussions of banned substances by Wagner or Mitchell, who was fired Monday.

The story, published Monday, said undercover reporters met with Wagner and Mitchell under the guise of seeking performance-enhancing drugs for an actor working on a film about athletics. Wagner and Mitchell are said to have offered to help purchase the PEDs.

Gatlin, 35, previously served a four-year suspension for a 2006 positive test. He also served a one-year suspension while at the University of Tennessee for a stimulant said to be in his prescribed attention deficit disorder medication.

In July, Gatlin won the 100 meters at the world championships in London in what was former world champion Usain Bolt's last competitive race.