NEW DELHI: Sonia Gandhi, president of India's ruling Congress party, vowed Wednesday to “correct the mistakes” that led to a mid-term drubbing in local polls and defended embattled Prime Minister Manmohan Singh.

“We will have to sit down and look at the situation and the results in every single state and then together work out a plan to correct the mistakes we have made,” Gandhi told reporters in a rare news conference.

Congress, which runs the federal government, won outright in only one of five states and suffered a humiliating defeat in politically vital Uttar Pradesh (UP) where the future of the Gandhi political dynasty was put to the test.

Sonia's 41-year-old son Rahul, next in line in the political family and widely tipped as a future prime minister, led campaigning in the giant northern region of 200 million people and had vowed to revitalise the left-leaning party.

But Congress slumped to fourth place and increased its presence only marginally in the 403-seat assembly to 28 elected members according to results published on Tuesday.

“Every election is a lesson for us whether we win or lose,” Italian-born Gandhi, wife of assassinated former prime minister Rajiv Gandhi, told reporters.

The media-shy leader also stuck by under-fire premier Singh when asked if he would be replaced amid mounting questions about his leadership half-way through his second mandate.

“There is no question (of replacing him),” she said while evading questions about who would be the candidate for the next national polls in 2014.

“I do not think the situation, the results will damage the UPA government,”she added, referring to the ruling United Progressive Alliance (UPA) coalition led by Congress.

Of the five states which held elections, Congress won only one with a clear majority -- northeastern Manipur.

As well as losing by a landslide in UP, it was turfed out of power in holiday state Goa and failed to dislodge the ruling party in agricultural heartland Punjab.

“We did have better hopes for Punjab,” said Gandhi. “Many voters in Goa were obviously unhappy with us and they voted against us.”

The Congress administration in Goa, like the national government in New Delhi, has been dogged by corruption allegations.

An investigation into illegal mining had led to pressure on Chief Minister Digambar Kamat. A report on the alleged flouting of environmental rules and tax evasion is due shortly.

Singh's administration meanwhile has spent much of the last two years fighting corruption scandals, from the Delhi Commonwealth Games to the bungled sale of telecom licences in 2008.

Sonia put the defeat in UP down to “poor organisation” and a lack of local leadership, while voters might also have held Congress responsible for inflation which was close to 10 percent for most of last year.

“Inflation could have impacted the elections,” she said.

As well as the success in Manipur, Congress scored a wafer-thin victory in mountainous Uttarakhand, but without a majority, meaning it must now try to put together a ruling coalition with smaller allies.

In Uttar Pradesh, India's most populous state, the regional Samajwadi Party (SP) won by a landslide, marking a comeback for a movement headed by a former wrestler which draws support from low-caste farmers and Muslims.

Their victory led to the demise of one of India's most colourful politicians, low-caste leader Mayawati whose scandal-plagued stint as chief minister ended on Wednesday with her resignation.