CPI(M) general secretary Sitaram Yechury on Thursday said his son Ashish died of COVID-19 in the morning.

Ashish, a journalist by profession who would have celebrated his 35th birthday on June 9, was recovering well at Gurgaon's Medanta Hospital, people close to the family added. They described his sudden death at 5.30 am after a two-week battle with the disease as a shock.

"It is with great sadness that I have to inform that I lost my elder son Ashish Yechury to COVID-19 this morning. I want to thank all those who gave us hope and who treated him - doctors, nurses, frontline health workers, sanitation workers and innumerable others who stood by us," Yechury said on Twitter.

Ashish, who studied at the Asian College of Journalism, Chennai, worked in several publications, including the Times of India in Delhi, before moving to Pune.

Journalists who worked with him remembered him as a mild-mannered and warm professional who was knowledgeable and well read.

The CPI(M) Politburo issued a statement announcing the death and offering its condolences to the family.

"We are deeply sorry to announce the passing away this morning (22 April) of Ashish Yechury, son of Sitaram Yechury and Indrani Mazumdar. He died of Covid related complications. He was 35 years old.

"The Polit Bureau conveys it deepest condolences to Sitaram and Indrani, his wife Swati, his sister Akhila and all other members of the bereaved family," the statement said.

As news of the death came in, condolences for the family poured in from political leaders, including from Prime Minister Narendra Modi.

"Condolences to Shri Sitaram Yechury Ji and his family on the tragic and untimely demise of his son, Ashish. Om Shanti, Modi said on Twitter.

Congress leader Shashi Tharoor said he was devastated by the news.

There is no greater loss for a parent to endure. May you find the strength to bear the inexpressible grief of your loss. My heart goes out to you at this painful time," he said.

"Deeply saddened and pained to hear about the loss of Ashish Yechury. I offer my heartfelt condolences to Comrade @SitaramYechury, his family and friends at this difficult time," tweeted DMK leader MK Stalin.

West Bengal Chief Minister Mamata Banerjee expressed her "shock" at Ashish's death.

"Shocked and very saddened to hear about the untimely passing away of Ashish, son of @SitaramYechury Ji. My deepest condolences to the grieving family," tweeted Banerjee.