BEIJING: China today warned Russian oil firm Rosneft and Vietnam against conducting oil exploration in the disputed South China Sea, also claimed by Beijing, without Chinese government permission, saying any such move would affect bilateral ties, regional peace and stability."I noted the report," Chinese foreign ministry spokesman Lu Kang said here while responding to a question about reports that Rosneft Vietnam BV - a unit of Russian state oil firm Rosneft - was drilling oil in an area of the South China Sea(SCS) also claimed by China.The report said Rosneft Vietnam BV is drilling at LD-3P well about 370 kms from Vietnam which reportedly is located "within the area outlined by China's nine-dash line" of the SCS.Lu said, "I would like reiterate that any country, organisation, enterprise or individual should not conduct exploration or development activities in waters in China's jurisdiction without the permission of the Chinese government"."We urge the relevant parties to respect China's sovereign rights, interests and jurisdiction and stop doing things that affect bilateral relations, regional peace and stability," he said.Lu's sharp reaction, warning the Russian firm came despite China's close ties with Russia , though China routinely objects to any drilling operations which falls into the area off Vietnamese coast.Earlier this year, China had objected to Vietnam's Ambassador to India Ton Sinh Thanh's comments inviting Indian investments in his country's oil sector.China has been opposing India's ONGC exploring oil in the wells claimed by Vietnam in the SCS. India has been asserting that ONGC's exploration is a commercial operation and not connected with the dispute.China claims almost all of the SCS while Vietnam, the Philippines, Malaysia, Brunei and Taiwan have counter claims.Today's reaction from China came after reports that Vietnamese officials ordered a batch of Chinese tourists to take off their T-shirts featuring a map of China and its so-called nine-dash line.Vietnam and China have been locked in a bitter struggle to assert their respective claims over the SCS, which in 2014 resulted in mass riots in Vietnam against Chinese companies.