"The passing away of Mme Guo would be felt in both countries as it marks the loss of a true symbol of their friendship in the modern era," Krishna said.
Mme Guo died in Chinese city of Dalian today. She was 96. Guo, herself a nurse hailing from China's Shanxi province, married Dr Kotnis in 1941, a year before his death in China.
She has been an honoured guest at many high-level diplomatic functions between China and India. She was a regular invitee at the Indian Embassy functions in China.
Dr Kotnis, who hailed from Sholapur in Maharashtra, died of epilepsy in China at the age of 32 years in 1942.
The External Affairs Minister said Kotnis had made great contributions in fostering friendship between the people of India and China.