Two investigations were ordered after six patients died due to alleged negligence at the state-run Saheed Laxman Nayak Medical College and Hospital in Odisha's Koraput, officials said on Wednesday.
The opposition Biju Janata Dal and Congress demanded action against those responsible for the death of the patients.
Three men and three women died on Tuesday night within a short time. While five patients died between 11 pm and 12 midnight, the sixth one succumbed at about 3.30 am on Wednesday.
Their families alleged that they were administered injections, following which they died.
The hospital superintendent Susanta Kumar Sahu said a departmental inquiry has been ordered.
"We have convened a meeting of all departmental heads. The patients who died on Tuesday night were admitted to the hospital in a critical condition. Prima facie, the deaths seem not to have been caused by any wrong injection. However, we will inquire into the allegations," he said.
Sahu said the patients in the ICU were in a serious condition and were administered the injection to control their dropping blood pressure.
He said two of the five deceased patients had abdominal injuries, while another was suffering from liver perforation.
"We suspect they died due to bleeding and septicemia. The fourth patient was being treated for stage 4 cancer, and the fifth was an accident victim, who was referred from Jeypore," he said.
The details of the sixth patient are not immediately available.
Director of Medical Education and Training (DMET) Santosh Mishra also ordered a separate inquiry into the allegations.
A five-member team, comprising three doctors from MKCG Medical College Hospital in Berhampur and two from SCB Medical College Hospital in Cuttack, will probe the allegations, he said.
"The team has been asked to submit the report by Thursday," Mishra said.
The health and family welfare department in a statement said, "Action will be taken against the person(s) if the team finds any negligence or alleged wrong injection leading to deaths."
The families of the deceased held a demonstration outside the hospital, following which police personnel were deployed.
The bodies were handed over to the families after post-mortem examination.
"Each family was given a cheque of Rs 10,000 from the district Red Cross fund. Arrangements were also made to transport the bodies to the villages of the deceased patients," a district official said.
Meanwhile, the Opposition Biju Janata Dal and Congress demanded action against the erring officials and alleged collapse of the health service system in the state.
Calling the death of patients at the medical college hospital as 'murder', Congress Legislature Party leader Rama Chandra Kadam demanded Rs 25 lakh each as compensation for the families of the deceased.
At a press conference in Bhubaneswar, BJD claimed that the death of the six patients at the hospital shows the alarming health service in the state.
"We demand for an impartial probe and white paper on the incident. Strict action must be taken against those responsible," BJD senior general secretary Bhrugu Baxipatra said.
Koraput district BJD president Jhina Hikaka and former MLA Raghuram Padal also held the state government accountable for the deaths.
The deceased persons were identified as Shukra Majhi, Rukuni Pentia, Phulmati Majhi, Bhagaban Parija, Bati Khara and Jagannath Pujari.