Opposition candidate Narendra Modi says he wants to "fulfil the dreams of 1.2 billion people" after sweeping to power in historic elections in India.
The final results have yet to be declared but the Hindu Bharitya Janata Party (BJP) already has enough seats to become the first majority government India has elected in 30 years.
As the polling data came in Mr Modi tweeted: "India has won. Good days are coming."
He then told crowds: "The heat of the election is over and the people have given their verdict which says that we need to take India forward to fulfil the dreams of India's 1.2 billion people.
"There are no enemies in democracy, there is only opposition. I will take your love and convert it into progress before I return."
The BJP has already surpassed the 272 seats needed to avoid a coalition, ending 10 years of Congress Party rule.
Narendra Modi declares victory on TwitterThe result is the worst ever for the Gandhi dynasty and follows what the BJP describe as a "people's revolution".
"This is the beginning of change, a people's revolution and the start of a new era," senior BJP leader Prakash Javadekar told AFP.
David Cameron has already spoken to Mr Modi and an invitation to Britain has been accepted.
The Prime Minister tweeted: "Congratulations @narendramodi on victory in India's elections. Keen to work together to get the most from UK-India relationship."
Barack Obama also invited Mr Modi to the United States, despite a previous decision to deny him a travel visa.
Narendra Modi is blessed by mother, Hira Ba, on the day of his victorySky's Neville Lazarus is outside the BJP headquarters in New Delhi and described the celebrations as "euphoric".
"They were expecting the number of seats to be high, but not this high," he said. "It's a vindication of Narendra Modi and his campaign.
"There is a mood of change in this country because the Congress Party has been reeling from the economic slowdown and corruption charges."
Mr Modi oversaw a modern campaign which utilised everything from holograms to WhatsApp.
Celebrations outside a counting centre in SiliguriThe stock market responded to his win by leaping 6%, sending the rupee to an 11-month high.
Mr Modi has been the top official in Gujarat state for a decade.
The 63-year-old is the son of a tea seller and has played on his humble roots during the election campaign, with references to his mother riding a rickshaw to cast her ballot.
His victory comes despite controversy over links to the paramilitary Hindu nationalist group Rashtriya Swayamsevak Sangh (RSS) - which some describe as neo-fascist.
As chief minister of Gujarat, Mr Modi was criticised for failing to apologise for religious riots in 2002 in which at least 1,000 people died - mostly Muslims.
He has denied any role in the violence and the Supreme Court declared he had no case to answer.
However, suspicions prompted the US to deny him a visa in 2005, while Britain maintained a diplomatic boycott on Mr Modi until 2012.