Ruling Congress party scion Rahul Gandhi's rejection of a government decree to protect convicted lawmakers has "dropped a bomb" on India's premier and made it uncertain whether he can remain in office, newspapers said Saturday.

Gandhi, the number two in the Congress party hierarchy, turned Friday on the government led by Prime Minister Manmohan Singh, calling a recently passed ordinance to prevent convicted criminals from serving in parliament "complete nonsense".

"Rahul drops bomb on PM, government," said mass circulation The Hindustan Times in a banner headline.

The newspaper said Gandhi, 43, had "undermined the position" of Singh at the worst possible time -- when he was on a visit to the United States to meet US President Barack Obama and address the UN General Assembly.

Shekhar Gupta, editor of the influential daily The Indian Express, said it was now up to Singh to decide whether he wanted to resign or "stoop to carry on as a loyal soldier".

Gupta said it would be "heartbreaking" if Singh, a renowned economist, chose to carry on in the face of this "humiliation".

The decree passed by the government seeking to overturn a Supreme Court decision that lawmakers should be barred from contesting elections if they are convicted of criminal cases was widely believed to have been steered by Singh.

"My opinion on the ordinance is that it is complete nonsense and should be torn up and thrown away," Gandhi told reporters in New Delhi on Friday at an impromptu news conference.

"If you want to fight corruption in the country... we cannot continue making these small compromises," Gandhi said.

The government had earlier argued the court decision was unfair, saying politicians can often fall prey to conviction on "frivolous grounds" and should have the right to appeal after convictions.

"For both the party and the government, nothing could have been more embarrassing than the Congress vice president's bombshell," the respected English-language daily The Hindu said.

"The ordinance cleared by the cabinet... has been a matter of much public debate," Singh said late Friday, adding, "the issues raised will be considered on my return to India."

The order awaits clearance of President Pranab Mukherjee but newspapers said Gandhi's intervention had virtually killed the decree.

Singh is widely expected to step aside after the government's five-year term ends.

Gandhi, whose family has given India three premiers, is portrayed as a reluctant leader and has resisted pressure to take cabinet posts. But he is being touted by supporters as the face of Congress ahead of elections due in 2014.

India's Hindu nationalist Bharatiya Janata Party has named controversial politician Narendra Modi, the chief minister of Gujarat state who is tainted by deadly anti-Muslim 2002 riots on his watch, as its candidate for premier.