Beijing, Jul 3 (PTI): The ongoing verbal spat between China and India today escalated as Beijing said the Indian Army's action to stop Chinese troops from constructing a road in an area near Sikkim is a "betrayal" of the position taken by successive Indian governments and India must pull back its soldiers.

Chinese foreign ministry spokesman Geng Shuang said that the Sino-India border in the Sikkim sector is well demarcated.

"By entering into the Chinese territory and obstructing Chinese troops' normal activities, India has violated the existing convention on the boundary and basic principle of international law and obstructed peace and stability of the boundary area," Geng told reporters at a briefing.

"We require the Indian side to withdraw their troops to the Indian side of the boundary and create conditions for he restoration of peace and stability in the relevant areas."

China and India have been engaged in a standoff in the Doka La area near the Bhutan trijunction for almost a month in what has been the longest such impasse between the two armies since 1962, when the two countries fought a brief war.

Sikkim, which became a part of India in May 1976, is the only state which has a demarcated border with China. The lines are based on a treaty signed with the Chinese in 1898. Doka La is the Indian name for the region which Bhutan recognises as Dokalam, while China claims it as part of its Donglang region.

Chinese foreign ministry spokesman Geng said India needs to observe the treaty and pull back its troops immediately. He dismissed Defence Minister Arun Jaitley's remarks that India of 2017 is different from what it was in 1962, saying China too is different and will take "all necessary measures" to safeguard its territorial sovereignty.

"Former Indian Prime Minister Jawaharlal Nehru endorsed the 1890 Sino-British Treaty on Sikkim in a letter to the then Chinese counterpart Zhou Enlai in 1959. Successive Indian governments have also endorsed this," he said.

"The India-China boundary in the Sikkim section is well demarcated. The action taken by India is a betrayal of the position taken by (successive) Indian governments," he said.

"What has happened is very clear, the Sikkim section of the boundary has already been defined by the 1890 convention between Great Britain and China. Doklam belongs to China."

Asked if there was a possibility of a meeting between Prime Minister Modi and Chinese President Xi Jinping during the G20 Summit in Hamburg in Germany this week, Geng said he has "no information at the moment" about the arrangements for bilateral meetings between Xi and leaders of other countries.

He, however, said the line for diplomatic communication between India and China is "open and smooth".

The standoff came to notice when China denied Indian pilgrims entry for Kailash Mansarovar Yatra through the Nathu La pass in Sikkim. At first, Beijing said it stopped the Yatra due to damage to roads in Tibet after rains and landslides.

Later China signalled the matter was related to the standoff between the two armies near Sikkim. The Sikkim route to Mansarovar was opened in 2015, enabling pilgrims to travel the 1500-km long route from Nathu La to Kailash by buses.

Today, Geng said the other route to Tibet through Lipulek pass is open as it is located in the middlesection where there is no dispute over boundary between India and China.

On the Indian Ministry of External Affairs statement on Friday that the construction road by Chinese troops in the disputed Doka La area would represent a significant change of status quo with "serious" security implications for India, The Chinese foreign ministry official said they have "noted" the statement by India.

"It evaded the 1890 convention between Great Britain and China relating to Sikkim and Tibet. But it is this convention which has confirmed the alignment of the boundary between the two sides at the Sikkim section. This convention has been recognised by successive Chinese and Indian governments and has been confirmed by the Indian governments in written form," he said.

"Prime Minister Nehru has affirmed in his letters to the Premier Zhou Enlai that the convention must be observed. That is the basic principle of international law. It is an obligation must be fulfilled by the Indian side," he said.

He also accused India of using Bhutan as a cover.

"In order to cover up the illegal entry of the Indian border troops, to distort the fact and even at the expense of Bhutan’s independence and sovereignty, they try to confuse right from wrong, that is futile," Geng said.

"We have no objection to normal bilateral relations between India and Bhutan but firmly opposed to Indian side infringing up Chinese territory using Bhutan as an excuse. The Bhutan side does not know previously that the Indian troops entered into the Doklam area, which is not in line with what is claimed by the Indian side," he said.

This is not the first time that such a transgression has happened at Doka La. The Chinese forces had in November 2008 destroyed some makeshift Indian army bunkers there.

Defence experts believe China wants to exert its dominance over the Chumbi Valley, which is a part of the southern reaches of Tibet. By claiming the Doka La area, Beijing wants to maximise its geographical advantage so that it can monitor all movements along the India-Bhutan border.

Since the standoff on June 6, when PLA bulldozers destroyed bunkers of the India Army claiming the area belonged to China, Chinese media have carried several peices warning India over escalating tension and "reminding" the Indian Army about the 1962 war.