Chandigarh: The Congress was on Saturday headed for a two-third majority in the 117-seat Punjab assembly, with veteran Amarinder Singh set to return as Chief Minister of the border state.

The Congress, which had been out of power in Punjab for a decade, had won 57 seats and was leading on 20 others, paving the way for the next Congress government in Punjab.

Prime Minister Narendra Modi spoke to Amarinder Singh and congratulated him.

The Aam Aadmi Party (AAP), which claimed it could win up to 100 seats, got only 18 and was leading on another three. Its ally, Lok Insaf Party, won two seats.

The saving grace for the AAP is that it will be the main opposition in the new assembly.

The Shiromani Akali Dal-Bharatiya Janata Party (BJP) alliance, which ruled Punjab since 2007, was set to finish a poor third with 17 seats. The Akalis won 12 seats and led on two. The BJP won three seats.

Ten ministers, including all four from the BJP, were defeated. 

Congress candidate Gurjeet Singh Aujla led on the Amritsar Lok Sabha seat by over 1.70 lakh votes. A by-election was held along with the assembly polls.

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

"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 told the media.

A former Chief Minister (2002-07), Amarinder Singh turned 75 years old on Saturday.

He was non-committal on having cricketer-turned-politician Navjot Singh Sidhu as Deputy Chief Minister in the next 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. A metal detector and more security personnel were deployed as the number of visitors increased.

Outgoing Chief Minister Parkash Singh Badal 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, led in Jalalabad over AAP's Bhagwant Singh Mann.

Cricketer-turned-politician Navjot Singh Sidhu 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.