Police in India have registered a criminal case against a leading businessman for allegedly circulating a joke insulting the Sikh community.
Mr Ambani is one of India's most powerful businessmen
Anil Ambani was charged by the police in northern Uttar Pradesh state with "insulting a religion or faith".
Mr Ambani is one of India's most powerful businessmen.
A statement released by his mobile telephone network, Reliance Communications, said that it was not responsible for text-messaged jokes.
"SMS jokes are provided by a third party vendor to the subscribers of telecom operators on a subscription basis," a company spokesman said.
"The vendor is responsible for the content provided. The vendor has already apologised to the subscribers as also to the company."
A local Sikh leader filed a complaint against Mr Ambani after the joke first began to circulate.
Mr Rajendra Singh Bagga said in his complaint that the joke was being sent by text on Mr Ambani's Reliance Communications mobile telephone network.
"We are a martial race. We fought for defending Hinduism and this joke is very insulting," Mr Bagga said.
A police official told the BBC that insulting a religion or faith could carry a punishment of three years in prison or a fine, if proved.
Earlier, members of the Sikh community in the city of Meerut held protests against the network allegedly circulating the joke.
Reports said that the joke had been sourced from a website well known for its collection of jokes around the Sikh community.
Community leaders say that Mr Ambani should apologise for circulating a "disgusting" joke.
But many others say that the registration of a criminal case against the businessman could have a political dimension.
Anil Ambani is known to be close to the opposition Samajwadi Party in Uttar Pradesh, while the complainant Mr Bagga is known to be close to the ruling Bahujan Samaj Party (BSP) chief minister, Ms Mayawati.
After coming to power this summer, Ms Mayawati's government swiftly cast doubt over the future of a special economic zone Anil Ambani is planning in the state.
Mr Ambani's Anil Dhirubhai Ambani Group is among India's top three private business houses with interests in communications, financial services, electricity, infrastructure and entertainment.