A senior government doctor involved in the fight against COVID-19 and a 34-year-old man, both diagnosed with the disease, died at a hospital here on Sunday, sources at the facility said.

Sixty-year-old Dr Biplab Kanti Dasgupta, posted as assistant director health services (equipment and stores), was initially admitted to Beliaghata Infectious Diseases hospital and later shifted to a private hospital in Salt Lake on April 18, where he succumbed to the disease.

'After he tested positive for COVID-19, he was first taken to Beliaghata ID hospital and then to the Salt Lake private hospital. The doctor was suffering from respiratory distress and other co-morbidities and had been on ventilator since he was admitted to the hospital. He died at 1.20 am on Sunday,' sources told PTI.

Expressing 'pain' at his death and extending condolence to the family of the doctor, Chief Minister Mamata Banerjee said his contribution to fighting the COVID-19 outbreak would encourage others.

'We have lost Dr Biplab Kanti Dasgupta, Assistant Director, Health Services, West Bengal in the early hours of today. He was Assistant Director of Health Services, Central Medical Stores. We are deeply pained with his untimely demise,' Banerjee tweeted.

'His sacrifice for the cause of ailing humanity will ever be in our hearts and will make our COVID warriors fight the deadly virus with even greater determination. My heartfelt condolence to Dr Dasguptas bereaved family members and colleagues,' she added.

Another patient from the city's Garden Reach area, who had tested positive for the disease earlier in the week, also died around 7 am at the same facility.

'The 34-year-old man was admitted to the hospital on April 23. He, too, had breathing problems and was put on ventilator. He died today morning,' they added.

After several calls made to senior government officials for more information on the two fatalities went unanswered, an official insisting that he not be named, said, 'The reason behind the death of the ADHS is still under investigation'.

West Bengal has reported a total of 541 COVID-19 cases so far. Of them, 18 have succumbed to the disease, according to the state health department.

The state government has constituted an audit committee of doctors which ascertains whether a patient of COVID-19 has died because of the disease or a pre-existing ailment.

According to Union health ministry, the number of COVID-19-stricken patients in the state stands at 571.

Chief Secretary Rajiva Sinha said on Friday that the audit panel has certified that only 18 of 57 fatalities were caused 'directly due to the disease'.

The rest 39 deaths were caused by other severe health conditions called co-morbidities in medical parlance.