New Delhi, Dec 12 (IANS): Pandit Ravi Shankar was a global ambassador of India's cultural heritage and a national treasure, Prime Minister Manmohan Singh said here Wednesday while condoling the death of the sitar maestro in a San Diego hospital.

"An era has passed away with Pandit Ravi Shankar. The nation joins me to pay tributes to his unsurpassable genius, his art and his humility, a national treasure and global ambassador of India's cultural heritage," the Prime Minister's Office (PMO) said in a message on micro-blogging site Twitter.

"India has lost an eminent son, the world of sitar has lost one of its ablest exponents ever and a shining light in the firmament of music has been extinguished," added the message.

Considering it a "personal privilege" to have known Ravi Shankar, the prime minister said it was difficult, often, to judge what was more remarkable: the man or his music.

"The nation was fortunate not only to be able to enjoy his music, but also to have him as one of its most effective cultural ambassadors across the world. His humanism, combined with his musical genius, helped him in building cross-civilisational contacts that served the world of music and benefited humanity at large," the prime minister said in his message.

"I pray that Pandit Ravi Shankar's soul finds eternal peace and that (his) family members be granted the strength and fortitude to bear this loss," he added.