India must withdraw its troops on the Doklam plateau or face ’’serious consequences’’, said a senior Chinese diplomat in New Delhi on Thursday.

The remarks mark a serious escalation in rhetoric over the ongoing tensions between the two countries, as their armies continue a six-week long stand-off near the India-Bhutan-China trijunction off Sikkim.

“The crossing of the boundary line by Indian troops into the territory of China using the pretext of security concerns for a 3rd party [Bhutan] is illegal,” Chinese Deputy Chief of Mission Liu Jinsong told journalists. “The troops should be withdrawn immediately, otherwise there will be serious consequences,” he said.

While refusing to elaborate on what the “consequences” would be, he said India’s action at Doklam was akin to “intruding into your neighbours house, and demanding that the neighbour leave to ensure your withdrawal.” He quoted Chinese President Xi Jinping’s obervation, “Military option is the fundamental guarantor of sovereignty.”

The comments, the sharpest Chinese statement yet, follows India’s rejection of the Chinese Ministry of Foreign Affairs’ 15-page position statement that was published on Wednesday. It had claimed that the number of Indian troops on the part of the Doklam plateau, contested between China and Bhutan, had reduced from 400 to “over 40”.

Indian government sources, however, had said that there was no reduction in Indian troops.

Repeating the charge, Mr. Liu said that as of Thursday, the Chinese Army had counted exactly 48 Indian soldiers. “Even one Indian soldier violating Chinese sovereignty is too many,” he continued, “We cannot bear that for another hour, another day, and they must be pulled out immediately.”

Chinese troops had notified India of their intention to refurbish a road in what it called its own territory on two occasions, on May 18 and June 8, the first time China has shared the specific details. It was “very shocking” for the Chinese side when the Indian troops came over to the disputed territory, he said.

More significantly, Mr. Liu alleged that India had not, as the government had maintained, come to the rescue of Bhutanese troops in the area.

When asked by The Hindu whether China was embarrassed by the Bhutan Foreign Ministry statement of June 30 that said the Chinese road construction activity was in “direct violation” of previous agreements, Mr. Liu said, “From the Bhutanese statement, nothing reflects that the Bhutanese side invited or knew before hand that India would send troops. Even if we accept a difference of view between China and Bhutan, we have many mechanisms to resolve them bilaterally.”

Bhutan’s Ambassador to India V. Namgyal told The Hindu he would not comment on the remarks by the Chinese envoy, saying that there was “nothing further to add” to the official statement.

When contacted for a response, the Ministry of External Affairs too declined to add to its statement of Wednesday, where it said that “peace and tranquility in the India-China border areas is an important pre-requisite for smooth development of our bilateral relations with China.”