Citing media reports that China has built shelters in the Depsang area in Ladakh, the Congress on Saturday questioned the government's "silence" over the issue and asked what steps were being taken by it to ensure status quo ante of April 2020.
Congress spokesperson Supriya Shrinate also attacked Prime Minister Narendra Modi over his handshake with Chinese President Xi Jinping at the G20 summit in Indonesia last month.
There was no immediate reaction from the government to the Congress' allegations.
While the Congress has been attacking the government over its handling of the border issues with China, officials have maintained that India has significantly enhanced its border infrastructure in recent years with the Centre giving a major boost to such efforts following the eastern Ladakh standoff.
"On November 15, Modi had met Xi Jinping, the Chinese head of state. He was not showing angry red eyes, he was in fact adorning a red shirt and I wonder what he talked about as he met Xi Jinping after the supreme sacrifice of 20 of our bravehearts," Shrinate said at a press conference at the AICC headquarters here.
Citing media reports, she said that in the area of Depsang, China has built temperature-regulated "shelters" that help any army personnel to be stationed permanently.
"Two hundred such shelters have been built by China in our territory 15-18 km inside the LAC (Line of Actual Control)," she alleged.
Why has there not been a single statement from Prime Minister Modi, his government or the Ministry of External Affairs, Shrinate asked.
"Remember, Depsang and Demchok are extremely strategic places for us. Also, remember China continues to occupy large parts of territory in the Depsang area," she said.
Shrinate also showed photographs of what she said were satellite images showing that China is doing "huge fortification" both on land and at sea.
"In fact, around the Pangong Tso lake area, China has built a PLA division headquarter, a garrison, artillery and anti-aircraft gun shelter," she claimed.
"China is getting emboldened by the abject pin drop silence of Modi and the clean chit that the prime minister has given that 'nobody has entered our territory'," Shrinate said.
Posing questions for the prime minister, Shrinate asked why the prime minister is "looking in the other direction when permanent shelters and fortifications are being built in the Demchok and the Depsang areas".
What steps are being taken to remove these fortifications and structures, she asked.
Shrinate also asked what steps are being taken to push away the Chinese from the Depsang and Demchok areas.
"More importantly, what is nationalism? You are so eager to issue certificates of nationalism to anybody that you warrant to. Is nationalism looking the other way and keeping the eyes shut and meeting the Chinese president with your open arms after 20 of your bravehearts have died," Shrinate said.
"The one question that Indian armed forces are raising, the one question several army personnel past and present are raising, defence experts are raising, is when will India return to status quo ante of April 2020 and what steps are being taken to ensure status quo ante is restored," Shrinate said.
She also asserted that the Congress will raise these issues at all forums available, including Parliament.
The eastern Ladakh border standoff between India and China erupted on May 5, 2020, following a violent clash in the Pangong lake areas. Both sides gradually enhanced their deployment by rushing in tens of thousands of soldiers and heavy weaponry.
As a result of a series of military and diplomatic talks, the two sides completed the disengagement process last year on the north and south banks of the Pangong lake and in the Gogra area.
The disengagement in the Pangong Lake area took place in February last year while the withdrawal of troops and equipment in Patrolling Point 17 (A) in Gogra took place in August last year.