China’s top market regulator has opened an antitrust investigation into Trip.com Group Ltd for suspected abuse of market dominance, the watchdog said in a statement.

The State Administration for Market Regulation (SAMR) said the probe was launched after a preliminary review and will examine whether the online travel platform violated China’s Anti-Monopoly Law through monopolistic practices.

“Based on earlier verification, the State Administration for Market Regulation has filed a case against Trip.com Group for suspected abuse of its dominant market position,” the regulator said.

No further details were immediately provided on the specific conduct under investigation or the time frame of the alleged violations.

Trip.com, China’s largest online travel agency, operates platforms including Ctrip, Qunar and Skyscanner, and plays a central role in the country’s tourism, airline ticketing and hotel booking markets.