Advani, an 85-year-old stalwart of the Bharatiya Janata Party (BJP) and a former deputy prime minister, resigned from all his positions in the party which he helped build into a national force. [break]
"He has submitted his resignation letter to the party chief," a source in his office said on condition of anonymity.
Indian media quoted from a resignation letter by Advani, the BJP´s prime ministerial candidate for the 2009 general elections, which made oblique references to Modi without naming him.

(FILES) In this photograph taken on June 6, 2011, India´s main opposition Bharatiya Janata Party (BJP) senior leader L.K. Advani gestures as he addresses media after presenting a memorandum to Indian President Pratibha Patil against the Congress government´s crackdown of spiritual guru Baba Ramdev´s hunger strike, at The President´s House in New Delhi. Veteran Indian opposition leader Lal Krishna Advani resigned on June 10, 2013, a day after his party chose hardliner Narendra Modi to lead next year´s election campaign, a source in his office told AFP. Advani, the 85-year-old stalwart of the Bharatiya Janata Party (BJP) and a former deputy prime minister, resigned from all his positions within the party, the source said. AFP PHOTO/Prakash SINGH/FILES
Advani said he was "finding it difficult to reconcile with either the functioning of the party or the direction in which it is going," according to the Press Trust of India.
"I have decided, therefore, to resign from the three main fora of the party, namely, the National Executive, the Parliamentary Board and the Election Committee," he said.
"Most BJP leaders are concerned just with their personal agendas," he added.
Advani´s campaign to build a Hindu temple on the site of a 16th-century mosque in the northern town of Ayodhya helped bring the party to national attention but also led to deadly religious riots.
Hindu zealots razed the mosque in 1992 which led to unrest in which over 2,000 people, mainly Muslims, died.
BJP spokesman Srikant Sharma told AFP that "every leader of the party will make every possible effort to convince him (to stay). His resignation has not been accepted."
Advani did not attend the meeting of the BJP´s national executive at the weekend which promoted Modi to election committee chairman, although the official reason given was illness.
Advani mentored 62-year-old Modi, a chief minister from the western state of Gujarat, and defended him against criticism that he failed to stop deadly anti-Muslim riots in 2002.
His resignation highlights the difficult road ahead for Modi who will need to win the backing of other senior BJP members as well as the party´s regional coalition partners.
Reports said that Advani will remain chairman of the opposition National Democratic Alliance, which comprises 13 parties, and will strengthen his case against Modi´s candidacy after roping in the support of regional partners.
Advani was born in Karachi in 1927 and joined the hardline Hindu outfit Rashtriya Swayamsevak Sangh (RSS) -- considered the BJP´s ideological parent -- when he was 14 years old.
He worked alongside close friend and future premier Atal Behari Vajpayee to build up the BJP and was named home minister and later deputy prime minister during the party´s stint in power from 1998 to 2004.
After his appointment Sunday, Modi said he had spoken to Advani and wrote on his official Twitter account that he was "honoured and extremely grateful to receive his blessings".
Blockade on Nepal was 'foolish thing': BJP leader