A Chinese environmental group said it filed a lawsuit against PetroChina for the illegal dumping of waste water from drilling operations in Kirin province. The All-China Environment Federation, a government-backed group, said it was calling on PetroChina, the country's largest oil producer, to pay nearly $10 million to cover the environmental damage associated with the discharge of waste drilling water, the official Xinhua News Agency reported Friday. PetroChina didn't issue a response to the lawsuit but said it sent a team to Kirin, which borders North Korea, to investigate the incident. No further information was provided. In a separate statement, PetroChina said an unnamed overseas shareholder filed a complaint in the U.S. District Court for the South District of New York against the company last week for alleged violations of securities laws in the United States. "The company will vigorously contest the complaint with its best efforts to protect the legitimate rights and interests of the company," PetroChina said its Nov. 26 statement. The details of the allegations and amount requested under the class action complaint weren't disclosed in the notice from PetroChina.