Trinamool Congress party supporters celebrate with colored powder in front of the residence of their party leader Mamata Banerjee on Saturday in Calcutta, India.India’s governing Congress party was headed to a resounding victory Saturday in the monthlong national elections, media reports said, setting off celebrations and claims of success by party leaders. The Trinamool Congress is an ally of the Congress party.

New Dehli, India ? The ruling Congress party swept to a resounding victory Saturday in India’s mammoth national elections, defying expectations as it brushed aside the Hindu nationalist opposition and a legion of ambitious smaller parties.

The strong showing by the party, which is dominated by the powerful Nehru-Gandhi political dynasty, laid to rest fears of an unstable, shaky coalition heading the South Asian giant at a time when many of it neighbors are plagued by instability, civil war and rising extremism.

Prime Minister Manmohan Singh declared victory, telling reporters that voters had given the Congress party-led coalition a “massive mandate.”

The left-of-center Congress, which has long tried to balance free market reforms with a vow to protect the downtrodden in this country of 1.2 billion people, wants a “stable, strong government which is committed to secular values,” he said.

The results left the Hindu nationalist Bharatiya Janata Party, the country’s other main party, vowing a period of introspection after they failed to capitalize on the economic uncertainty and increased turmoil in Pakistan, India’s longtime rival.

“We will analyze these results in detail,” said Arun Jaitley, a senior BJP leader conceding defeat. “The BJP accepts the mandate of the people of India with all humility.”

With most votes counted, the Election Commission said the Congress-led alliance had won — or was leading in — races for 254 seats in the 543-seat Parliament. The BJP alliance came up short with 153. The Congress party alone, without the support of its coalition allies, had won or was leading in 204 seats, putting it far ahead of all other parties.

While the results were a clear victory for the Congress coalition it still leaves it short of the 272 seats needed to govern alone and will require the support of other parties. India has been ruled by coalition governments for most of the last two decades.