The fight between the United States and the world’s anti-doping regulator over the handling of positive tests by elite Chinese swimmers has escalated in recent weeks and drawn in a powerful new player: the White House.

The regulator, the World Anti-Doping Agency (WADA), informed the White House last month that its officials were seeking to bar the administration’s representative from any deliberations about positive tests by Chinese athletes at the agency’s leadership meeting this week in Turkey.

The attempt to exclude the official, Dr. Rahul Gupta, who is the director of the Office of National Drug Control Policy, is seen as part of a larger effort by WADA to push back on U.S. criticism of the agency’s handling of the doping allegations and to try to shut down an FBI investigation into the matter.