Congress leader Rahul Gandhi on Wednesday alleged it was clear that Prime Minister Narendra Modi was protecting Gautam Adani as he did not order an inquiry into the allegations levelled against the industrialist by a US-based research firm.

He said the prime minister did not answer the questions posed to him.

"I am not satisfied, but it reveals the truth. There was no talk of an inquiry. If he is not a friend, then he should have agreed to an inquiry. There was no probe into shell companies in defence sector and benami money is changing hands, but the prime minister did not say anything on that.

"It is clear that the prime minister is protecting him," Gandhi told reporters after the prime minister's reply to the motion of thanks on the President's address.

Gandhi said this is an issue of national security and concerns the country's infrastructure and the prime minister should have said that there will be a probe into the allegations.

"This is a very big scam. He did not even say that. He (PM) is surely trying to protect him (Adani) and I understand this and there are reasons for it," he said.

Asked if he got the answers to his questions, the former Congress chief said, "I did not get any reply from the prime minister to my questions."

"The prime minister was shell-shocked. He was in shock and there was no answer. I have not asked any complicated question. I only asked how many times he (Adani) has gone with you. How many times did he meet you. I posed simple questions but got no answers," he said.

"I am not satisfied, but it reveals the truth," he said when asked if he was satisfied with the prime minister's reply.