"We also want to ask the prime minister about the Chinese intrusion. How did the Chinese soldiers enter India?" Tewari asked at an online press conference.
Indian and Chinese troops have been engaged since May 5 following a violent clash in Pangong Tso in eastern Ladakh.
The trigger for the face-off was China's stiff opposition to India laying a key road in the Finger area around the Pangong Tso Lake, besides construction of another road connecting the Darbuk-Shayok-Daulat Beg Oldie road in Galwan Valley.
"Who is responsible for this? Will the government decide its accountability? The country wants to know this," Tewari said.
The Congress leader said Modi should tell the country that from May 5 till now, how much of India's land had been occupied by the Chinese army.
"Is it a fact that the Chinese have illegally occupied 40-60 sq km of Indian territory?" he asked.
"We want to ask the prime minister what the government is doing to remove the Chinese army from the Pangong Tso Lake in Galwan Valley, where China is sitting with its soldiers and tents," he asked.
He accused the Centre of trying to push the issue in cold storage
Hitting back at Ravi Shankar Prasad for his attack on Congress leader Rahul Gandhi, Tewari said the Union law minister made a "very unfair and completely irresponsible" political attack.
According to Tewari, it is unfortunate that rather than answering questions, the government was using "abrasive language" against the opposition party.
He said the government should direct India's national angst against those who have encroached upon Indian territory, rather than the Opposition.
"We want to tell them that patriotism and nationalism is not the exclusive monopoly of the NDA-BJP and much less the law minister," Tewari said. "Asking hard questions to the government is not unpatriotic, not replying to them is unpatriotic."
Tewari added that the Congress was posing questions as a responsible opposition party.
He underlined that when there were questions of security, unity, integrity, sovereignty, people hoped that the prime minister, defence minister, defence secretary or any other officer would come and tell the country about the situation, adding that there had been no such initiative.
The names of Pangong Tso Lake, Galwan Valley, Naku La were never heard of by Indians, he said, but today "even children know about it because these are all the places where Chinese soldiers have encroached" on Indian land.
The situation in the area deteriorated after around 250 Chinese and Indian soldiers were engaged in a violent face-off on May 5 and 6. The incident in Pangong Tso was followed by a similar incident in north Sikkim on May 9.
The India-China border dispute covers the 3,488-km-long Line of Actual Control (LAC).