One more person injured during the violent unrest in Sunsari district has died while undergoing treatment, raising the death toll from the clashes in Dewanganj to three.

Twenty-one-year-old Rabindra Kumar Mehta of Dewanganj-3 died on Tuesday at the Tribhuvan University Teaching Hospital, where he had been receiving advanced treatment, police and family members said.

Superintendent of Police Pushpa Raj Malla of the Sunsari District Police Office confirmed the death.

"He had been referred to Kathmandu for further treatment. We have now received confirmation that he died during treatment," Malla told Kantipur.

A relative, Roshan Mehta, said Rabindra succumbed to his injuries on Tuesday after several days in intensive care.

Rabindra was among 10 people wounded when security personnel opened fire while trying to disperse violent clashes between two groups in Kaptanganj of Dewanganj, on July 26.

After receiving initial treatment, he was airlifted last Friday from Birat Nursing Home in Biratnagar to Kathmandu. He had suffered a gunshot wound to his left thigh that severely damaged a major artery. Surgeons in Biratnagar performed emergency vascular surgery, but his condition continued to deteriorate, prompting doctors to refer him to the teaching hospital.

As complications and infection worsened, doctors were forced to amputate his left leg in an attempt to save his life. Despite further treatment, he died on Tuesday.

Another critically injured victim, 18-year-old Amit Yadav of Dewanganj-3, remains hospitalised at the National Trauma Centre. He was transferred from Nobel Teaching Hospital in Biratnagar to Kathmandu aboard a Nepal Army aircraft for specialised treatment.

Six other people injured in the violence are being treated at hospitals in Biratnagar. Doctors said their conditions are gradually improving.

Rabindra is the third person to die from injuries sustained in the clashes.

Earlier, Om Prakash Mehta, 28, of Dewanganj-4 and Jaya Prakash Mehta, 21, of Dewanganj-3, also died while undergoing treatment after being shot during the incident.