LEH/NEW DELHI: Chinese troops are reported to have entered 25 to 30km deep into Indian territory in Burtse area in Ladakh where they had pitched their tents last year that had led to a tense three-week standoff.Official sources said on Monday a patrol of Indian troops noticed the People's Liberation Army ( PLA ) personnel yesterday while moving from their base towards the higher 'New Patrol base' post in Burtse area of North Ladakh in Jammu and Kashmir. The area is at an altitude of 17,000 feet.The sources said the troops after walking barely 1.5km from their base spotted the Chinese personnel in Indian territory 25 to 30km from the perceived Line of Actual Control ( LAC ).Adhering to newly drafted Standard Operating Procedures, the Indian troops returned back to their base.The troops went on a patrol again to the 'New Patrol base' post in the wee hours of Monday.However, the team found no change in the situation as it noticed the PLA personnel still sitting on the ground with flags reading "this is Chinese territory, go back" in their hands.A Quick Reaction Team had also accompanied the Indian patrol but nothing could be achieved as Chinese refused to budge from their position, the sources said, adding finally Indian troops returned to their base and informed their higher ups.Udhampur-based Army spokesman Col S D Goswami denied that any such incident had taken place but said there was no commonly delineated LAC between India and China which led to transgressions."There are areas along the border where India and China have differing perception of LAC. Due to both sides undertaking patrolling upto their respective perception of the LAC, transgressions do occur.However, no incursion or encroachment of Indian Territory by China has taken place along the India-China border," the spokesperson said in response to an email query.He said India regularly takes up any transgression with the Chinese side through established mechanisms such as flag meetings, border personnel meetings and normal diplomatic channels like Working Mechanism on Consultation and Coordination on India-China Border Affairs.At these meetings, the issues are resolved through the provisions of various agreements between India and China, he added.According to sources, the Indian border patrol attempted to reach the 'New Patrol Base' from a place known as 'Nallah one', near its base.A satellite image of the area was likely to be taken to ascertain whether the Chinese PLA have pitched in tents like it did last year, the sources said. The sources, however, hinted that there was a possibility of some tents being erected by the Chinese troops to facilitate their movement deep into the Indian territory.The Burtse area, which is adjacent to Daulat Beg Oldie( DBO ), forms part of huge Depsang plains perceived by India as their own territory.However, the Chinese side have been claiming it to be part of their territory as it gives them a tactical edge over the area including the air field which was operationalized by the Indian Air Force(IAF) last year for a brief while.This area was in news last year due to 21-day stand off between India and Chinese troops which ended after four flag meetings between the two sides. Chinese PLA had pitched five tents in the area and claimed that it was a part of their territory.