The prime minister was responding to the criticism by Congress President Rahul Gandhi and SP leader Akhilesh Yadav of the train, which had developed a snag on its return journey from Varanasi to Delhi on Saturday, hours after its inaugural run.

"Some persons targeting and mocking at semi-high speed train. This is unfortunate. This is an insult to engineers and technicians involved in the project.  People should remain alert against such persons who are insulting engineers and technicians and mocking the country," the PM said while addressing a public meeting here.

He asked the people not to get "demoralised by those surrounded by negativity".

"I salute engineering professionals, who will in future make a bullet train in India and run it also...I am getting letter of people who are hurt", the PM said asking them, "Whether it is right to insult engineers and technicians? Is mocking them right. Can they be pardoned? Should they not be given right punishment at the right time."

He said the "country is proud of them (engineers) and their hard work."

The Congress President had attacked the Make in India campaign and Prime Minister Modi after the Vande Bharat Express suffered a snag on its maiden return journey on Saturday.

"Modi ji, I think Make in India needs a serious rethink. Most people feel it has failed. I assure you we in the Congress are thinking very deeply about how it will be done," Gandhi had said.

Samajwadi party chief Akhilesh Yadav had on Sunday taken to Twitter to attack the BJP government after the Vande Bharat Express developed a technical snag.

"After the inauguration, fumes were seen in Vande Bharat train, power failure inside coaches, snag developed in brakes after which train came to a halt. Vande Bharat is a story of development. Farmers are angry, youths are unemployed, security system has collapsed and country's economy shattered," Akhilesh had tweeted.

Modi also paid tributes to Ramesh Yadav of Varanasi, who was killed in the Pulwama attack.

"Entire country will be forever indebted to families of those soldiers who laid lives for the country", he said.