Bollywood's "first superstar" Rajesh Khanna has died at the age of 69, his family has said.

The actor had been in and out of hospital in recent weeks. The cause of his health problems was unclear.

Khanna made his name playing the romantic lead in a string of films which were massive hits in the 1960s and 1970s.

The actor starred in more than 160 films, including hits such as Kati Patang, Aaradhana, Anand and Amar Prem.

He had a huge following and was mobbed by fans whenever he appeared in public.

Khanna died at his family home in Mumbai on Wednesday, the Press Trust of India reported. He had been discharged from a hospital in the city on Monday.

Scores of fans gathered outside Aashirwad, his home on Carter Road in Mumbai's Bandra area, following the news of his death, the agency said.

"He has gone to a very nice and heavenly place. We are very happy that he had gone there," his actor son-in-law Akshay Kumar told reporters.

"I hope everybody there, whoever is watching him, can just say a little prayer for him," he said.

Meanwhile, tributes have been pouring in for the superstar on the micro-blogging site, Twitter, where fans have been remembering his best dialogues and songs from his hit films.

PM Manmohan Singh led the tributes with his tweet: "I convey my heartfelt condolences to the members of the bereaved family and countless fans and admirers of Rajesh Khanna."

Wrote actor Anupam Kher: "Rajesh Khanna gave us a crash course in Romance. He introduced us to a special twinkle in the eye that made us feel good about ourselves."

Director Karan Johar tweeted: "The magic... the mannerism... the mania of RAJESH KHANNA is inscribed in every archive of Indian cinema... Forever.... RIP SIR!!!"

Filmmaker Mahesh Bhat wrote: "When we lose a loved one, something within us dies. Our generation loved Rajesh Khanna. Today a bit of us dies with this enigmatic star."

Actress Shabana Azmi tweeted: "He was the SUPERSTAR like no other. Did 10 films with him. Met him last at Apsara awards. Pale shadow of himself but smile as winsome."

Popularly called "Kaka" by his fans, the actor won a host of industry awards during his long career, although he was only recently seen in his first television commercial.

During the peak of his popularity, there were reports of his female fans marrying his photographs.