Bharatiya Janata Party (BJP) leader L.K. Advani's comments favouring Gujarat Chief Minister Narendra Modi as a possible successor are causing heartburn in the party - and concern among its allies.

Advani's admission in his autobiography that he disagreed with then prime minister Atal Bihari Vajpayee's suggestion to sack Modi in the wake of the 2002 sectarian violence has not gone down well with some BJP allies. And some in the BJP believe that Advani should hardly have made any pro-Modi remarks at a time when the BJP is trying to attract new members to the National Democratic Alliance (NDA) ahead of parliamentary elections.

Despite his electoral triumph in Gujarat, Modi remains a sort of political untouchable to many in the NDA. These particularly include the Trinamool Congress and the Janata Dal-United (JD-U).

"How does Advani hope to have wider acceptability if he proudly announces his preference for Modi?" asked a disappointed BJP leader on condition of anonymity.

The leader further told IANS: "There is considerable consternation among our allies too. We are receiving phone calls from allies asking why he had to mention Modi?"

In his autobiography "My Country, My Life", Advani admitted what was widely known but never confirmed: that Vajpayee wanted to dismiss Modi after the 2002 Gujarat riots. It was Advani, then deputy prime minister, who forced the NDA prime minister not to do so.

Adding salt to injury, as far as BJP leaders are concerned, has been Advani's preference for Modi as his possible successor.

"Many allies are not sure how far Advani would be acceptable to a wider cross-section as Vajpayee was. It is even more difficult to project Advani as a moderate after he has declared Modi to be his successor," grumbled a JD-U leader who too did not want to be identified by name.

BJP leaders admit that Advani's efforts - including his surprise visit to Congress president Sonia Gandhi's house to hand over a copy of his biography - are aimed at shedding the Hindu hardliner image he has enjoyed.

Some of his colleagues, however, feel that this is not happening although the autobiography has been released at a time when the BJP is trying to pick up more allies ahead of the 2009 general election.

"I don't know what purpose this book will serve," said the JD-U leader. "Advani has criticised Vajpayee, Jaswant Singh, Sonia Gandhi and Manmohan Singh - and praised only himself and Modi."

Trinamool Congress leader Mamata Bannerjee, who wants her Muslim vote bank in West Bengal to be intact, is one of the BJP allies who will be worried by the praise Advani - the BJP's prime ministerial candidate - has heaped on Modi.

BJP leaders say that Advani's objective is to replicate a Vajpayee image that proved to be so essential in keeping the multi-party NDA together.

The former prime minister's persuasive skills and moderate political approach, on more than one occasion, restrained restive NDA partners from quitting the coalition.

Advani, his colleagues say, has to fit into Vajpayee's shoes if he is to head a coalition after the 2009 polls. Most of the BJP allies are intrinsically opposed to the party's core Hindutva ideology.

Naturally, the signals sent out by Advani are raising apprehensions among existing and potential NDA allies.

Advani, in his memoirs, has spoken disparagingly of National Conference leader and former Jammu and Kashmir chief minister Farooq Abdullah. Abdullah and son Omar joined the NDA when not many Muslims were ready to look at the BJP.

Said a BJP leader: "We had decided to expand the NDA and include more allies to facilitate our return to power. We are trying to persuade (AIADMK leader J.) Jayalalitha to rejoin NDA. At such a crucial juncture such damning references to a former ally will not do us much good."