The Congress party on Saturday swept back to power in Punjab after a decade, with veteran Amarinder Singh set to return as Chief Minister of the border state.

The Congress, headed for a two-thirds majority in the 117-seat Punjab assembly, worsted the Shiromani Akali Dal-Bharatiya Janata Party combine. The party's win also turned on its head the BJP's 'Congress Mukt Bharat' (Congress free India) slogan.

The Congress won 76 seats and was leading in one more.

Having won Punjab for his party on his 75th birthday, Amarinder Singh said his first priority would be to eradicate drugs from the state.

Prime Minister Narendra Modi, whose BJP was piggy-backing to power with the Shiromani Akali Dal in Punjab for the past decade, spoke to Amarinder Singh and congratulated him on the victory.

The Aam Aadmi Party (AAP), which had run a high-voltage campaign in the state and claimed it could win up to 100 seats, got only 20 seats. Its ally, Lok Insaaf Party, won two seats.

The AAP beat the Akali Dal to emerge at second spot, and will be the main opposition in the new assembly.

The Shiromani Akali Dal-Bharatiya Janata Party (BJP) alliance, which ruled Punjab since 2007, finished a poor third with 18 seats. The Akalis won 15 seats while the BJP won three seats.

Ten ministers, including two from the BJP, in the Parkash Singh Badal government were defeated.

Congress candidate Gurjeet Singh Aujla won the Amritsar Lok Sabha seat comprehensively by 199,189 votes. The by-election was held along with the assembly polls.

"The people of Punjab have given us a big mandate. Our first priority will be to eradicate drugs from Punjab. I have vowed to finish drugs within four weeks," a visibly happy Amarinder Singh, who was Chief Minister from 2002-07, told the media.

He was non-committal on having cricketer-turned-politician Navjot Singh Sidhu as Deputy Chief Minister in the new government.

"That will be decided by Congress Vice President Rahul Gandhi. All ministers will be decided by the party leadership."

In Chandigarh, security was enhanced outside the private bungalow of Amarinder Singh in the upscale Sector 10 on Saturday morning itself as early trends started coming in. A metal detector and more security personnel were deployed as the number of visitors increased.

Outgoing Chief Minister Parkash Singh Badal, a five-time Chief Minister, accepted defeat and said he will resign on Sunday.

Badal, 89, the oldest Chief Minister in the country, said: "I am grateful to the people of Punjab for giving me an opportunity to serve them. I am fully satisfied with all the things I was able to do. I seek forgiveness for any mistakes."

On the Lambi assembly seat, where Amarinder Singh had challenged Badal on his (Badal's) home turf, Badal won by 22,770 votes. But Amarinder Singh won his traditional Patiala Urban seat by over 52,400 votes.

The Chief Minister's son Sukhbir Singh Badal, the Akali Dal President, won in Jalalabad over AAP's Bhagwant Singh Mann by a margin of 18,500 votes.

Cricketer-turned-politician Navjot Singh Sidhu, who won from the Amritsar-east assembly seat by over 42,000 votes, dubbed the Congress victory as its "revival" and blamed the Akali rout on its leadership's "arrogance and turning the treasury into personal property".

Sidhu, who left the BJP to join the Congress last year, also attacked Delhi Chief Minister Arvind Kejriwal. "Kejriwal had wrong intentions. It is a huge defeat for him."

Prominent AAP winners included Sukhpal Singh Khaira, H.S. Phoolka and Kanwar Sandhu. The AAP also finished second in 26 constituencies.

Prominent losers included former Chief Minister Rajinder Kaur Bhattal (Congress), Sunil Jakhar (Congress), Ludhiana MP Ravneet Singh Bittu (Congress), Punjab ministers Adaish Pratap Singh Kairon, Tota Singh, Sikander Singh Maluka and former Army chief, Gen J.J. Singh.

The Congress ended up with a vote share of 38.5 per cent from the votes polled in the election. The Akali Dal got 25.3 per cent while its ally BJP got 5.3 per cent. The AAP finished with 23.8 per cent of the vote.