A small time TV producer is suspected to be behind threats to actress Mona Singh who plays the protagonist in the highly popular soap "Jassi Jaissi Koi Nahin".

Singh filed a police complaint earlier this month after a telephone caller threatened her.

Police officials say the caller, who called himself Vicky, did not demand any money from Singh but tried to persuade her to act in a television serial.

The name of the producer who is suspected to have employed Vicky has been kept a secret to allow investigations.

In her complaint, Singh alleged that Vicky, claiming to be calling from Nairobi, had telephoned her demanding that she work for a certain television company.

The caller even threatened to harm her if she didn't stop working on "Jassi Jaissi Koi Nahin", which is aired on Sony channel, according to police.

Singh plays the bespectacled, simple yet highly intelligent middle class girl Jassi, winning the hearts of millions of Indians who identify with her.

Police have arrested a few known gangsters who specialise in extorting money from professionals, according to sources. All of them are suspected to have been employed by Vicky, police said.

Police here say extortionists based in Mumbai often make threatening telephone calls using foreign SIM cards or even satellite phones to give the impression that they represent gangsters Dawood Ibrahim or Chhota Rajan.

"A lot of small time gangsters have been caught using the same methods," says a police officer.

Police have provided protection to Singh, who has also signed up with a private security agency.