By Zubair Ahmed BBC News, Mumbai

Salman Khan strongly denies any links to the underworld

Authorities said the actor's phone was tapped for two months beginning August 2001 to see if he had any links with Mumbai's underworld crime syndicates.

The Hindustan Times last week published transcripts of a tape in which Mr Khan is said to have boasted of such links.

The actor denies the voice in the tapes is his.

The state government promised appropriate action against the actor if links with the underworld were established.

Voice samples

Maharashtra home minister, RR Patil, said that during the tapping a member of one of the crime syndicates in Mumbai (Bombay) called Mr Khan on his phone.

Mr Patil did not give any details of the conversation.

Khan denies ex-girlfriend Aishwarya Rai's claim he abused her

He said the regular conversations between the two did not necessarily mean the actor had any connections with the underworld dons.

Mr Khan strongly denies any such links.

The Hindustan Times' transcripts were purportedly of a phone conversation between Mr Khan and his then girlfriend, actress Aishwarya Rai.

The Maharashtra government did not say this particular conversation was recorded at its behest.

Samples of Mr Khan's voice and that of Ms Rai are being examined in a government laboratory.

Noted criminal lawyer, Majeed Memon, said Mr Khan and many other Bollywood stars were questioned at the time about whether the 2001 film Chori Chori Chupke Chupke (Stealthily, Quietly) was financed by Mumbai's underworld.

Mr Memon said the actor had starred in the film and the police had investigated thoroughly to see if he was responsible in any way for getting slush money for the film.

He was subsequently found not to have any links with the underworld.

Analysts have asked why, if Mr Khan's phone was indeed being tapped and links were proven, the police had failed to take action against him in the past four years.

Mr Khan, one of the most popular Bollywood stars, is no stranger to controversy.

He is currently facing a court case for his alleged involvement in a hit-and-run incident.

He has also been accused by Ms Rai, a Bollywood heartthrob, of ill-treating her.

Ms Rai's friend and fellow actor, Vivek Oberoi, has accused Mr Khan of making threatening calls to him.