NEW DELHI: Firebrand anti-corruption champion Arvind Kejriwal was clearing his desk Saturday after quitting as Delhi's chief minister in a move that leaves him clear to lead his party into battle in a looming general election.

Only 49 days after his upstart Aam Aadmi (“Common Man”) Party took power in the capital, Kejriwal resigned on Friday night when the country's two main parties combined to thwart his efforts to bring in a new anti-corruption bill.

Kejriwal, whose stunning breakthrough in the Delhi state elections in December highlighted public anger towards the political establishment, launched a blistering assault on Prime Minister Manmohan Singh's Congress party and the Bharatiya Janata Party (BJP) in his resignation speech.

Newspapers said his decision to quit so soon after taking power appeared part of a wider strategy which would free Kejriwal to lead his party's campaign in a general election due by May.

The anti-corruption bill was the main plank of Kejriwal's manifesto in the Delhi state election, the first campaign that his party had ever fought.

Although Aam Aadmi only won 28 of the 70 assembly seats, it was able to take power after Congress agreed to give it backing from outside.

However Congress refused to support the Jan Lokpal bill, which included plans to set up an anti-corruption commission, in a vote Friday on procedural grounds.

In his speech to supporters on Friday, the 45-year-old accused Congress of reneging on an earlier promise to back the bill.

- 'Broken promises' -

“Congress had promised us, in writing, that they would support the bill but when we tried to present it before the assembly today both they and the BJP came together to block it,” Kejriwal said.

“This is the first time in India's history that both the BJP and Congress have come together... They have exposed themselves and shown their true face.

”In his typically fiery address, the former tax inspector also accused the two parties of taking orders from Mukesh Ambani, India's wealthiest man who heads the giant Reliance Industries conglomerate.

The BJP is expected to win the national polls, but it will need support from smaller parties to clinch victory.

Although Kejriwal only formed his party a year ago, its remarkable showing in the Delhi election shocked the country's political establishment.

Congress, which has been badly damaged by a series of corruption scandals at national level, saw its number of seats slashed from 43 to just eight.

Aam Aadmi has said it plans to contest the national elections although analysts say it is unlikely to win much support outside major cities such as Delhi and Mumbai due to its lack of infrastructure and funding.

Newspapers said that Kejriwal's resignation represented something of a gamble for his party, with many of the voters who backed him in December unhappy at his decision to walk so soon.

“As AAP moves to launch an audacious Lok Sabha (parliamentary) campaign, the political greenhorn who humbled both Congress and BJP will also have to answer questions about its commitment to governance and if it has the vision to be a long-term player,” said The Times of India.

The Hindustan Times said that Kerjiwal's resignation was part of a plan that would allow him to spearhead the general election campaign.

“The decision to quit is part of AAP's bigger strategy,” the paper said.

“It hopes to paint the Congress and BJP as the villains of the piece who did not let his government fulfill its promises, and is banking on the people to bring it back to power on its own.”

During his administration's brief time in office, Kejriwal unveiled a series of headline-grabbing initiatives, including a graft hotline aimed at stemming the rampant corruption of police and bureaucrats.

After shunning the usual official car and instead taking the subway to his swearing-in ceremony, Kejriwal then slashed electricity costs and announced free water supplies.

But while his elevation to one of the most important political posts in India was initially widely welcomed as a much-needed shock to the system, the former tax inspector has since come in for criticism over a series of stand-offs with the authorities.

The self-styled “anarchist” staged a sit-in on the pavement close to the national parliament last month, triggering chaos in the city centre, as part of a push to be given greater powers of control over the police.

In Delhi, the BJP will be given the opportunity to form an alternative administration before any decision is made on holding fresh elections.

The party is the biggest faction in the assembly, having won 32 seats in December.