Singer Krishnakumar Kunnath, better known by his stage name KK, died in Kolkata on Tuesday night, PTI reported. He was 53 years old.

KK died shortly after performing at a concert at the city’s Nazrul Manch auditorium. The singer collapsed at the hotel where he was staying after the performance. Doctors at the Calcutta Medical Research Institute said that KK had died by the time he was brought to the hospital, NDTV reported.

Doctors suspect that he died due to a cardiac arrest. However, a Kolkata Police official said that a post-mortem will be conducted on Wednesday to identify the exact cause.

The Nazrul Manch authorities released a video of his last performance on Tuesday.

KK shot to fame with his debut album Pal, released in 1999, and went on to sing several popular tunes for Hindi movies in the 2000s and 2010s. He also recorded songs in Tamil, Telugu, Kannada, Malayalam, Marathi and Bengali.

On Wednesday, the West Bengal government gave a gun salute to honour the singer, PTI reported.

Chief Minister Mamata Banerjee paid floral tributes to KK. His body will be taken to the Netaji Subhas Chandra Bose International Airport to be later transferred to Mumbai, reported PTI.

Banerjee was also seen consoling KK’s wife Jyothy and other family members, who were present at the venue.

Political leaders, musicians and film personalities expressed shock at the singer’s death.

Prime Minister Narendra Modi said that he was saddened by KK’s untimely demise. “His songs reflected a wide range of emotions as struck a chord with people of all age groups,” he wrote in a tweet. “We will always remember him through his songs.”

Congress MP Rahul Gandhi described KK as “one of the most versatile singers” of the Indian music industry. “His soulful voice gave us many memorable songs,” he said.

Musician Papon prayed for strength to KK’s family and said that his songs “will be forever with us”.

Another singer Harshdeep Kaur said that KK’s death was heartbreaking, and that she could not believe that he was no more.

Singer and Trinamool Congress MLA Babul Supriyo described KK as a “great singer and a family man”, ANI reported. “He lived a simple and calm life, never saw him attending many parties,” he said. “Have lots of memories with him.”

Actor Akshay Kumar said that he was “extremely sad and shocked” to hear about KK’s death.

Actor R Madhavan said that the world “lost a wonderful human and a great voice”.