At least two persons were killed and four others injured in West Bengal on Thursday after a mortar shell, floating in the floodwaters of Teesta river, exploded after the victims recovered it from the water along with other stuff and tried to fiddle with it, police said.

Police believe the mortar shell belonged to the Indian Army and was among various military equipment, including firearms and explosives, that were washed away from the Singtam camp and other military bases in Sikkim following Wednesday’s cloudburst and flash floods that ravaged large parts of the state.

The explosion took place in Chnapadanga village in Jalpaiguri district's Kranti block in Mal subdivision after a youth, who went fishing in the river, recovered the shell and took it home. “It’s possible that the victims were trying to sell it as scrap metal and tried to break it open when it exploded,” a police officer said.

"The four injured persons have been admitted to the Jalpaiguri super-specialty hospital. A thorough probe into the matter has started," said the district’s deputy superintendent of police (crime) Bikramjit Lama. The identity of the two deceased were yet to be affirmed, he said. The condition of at least two injured persons is extremely critical, sparking apprehensions that the death toll could increase.

“We are yet to ascertain the scale of loss the Army has suffered on account of the Sikkim flash floods,” said Wing Commander Himangshu Tiwari, Bengal PRO of the defense ministry. “But there’s no doubt that the loss is substantial, both soldiers and equipment.”

“However, all arms and ammunition have multiple safety features built within them and they are unlikely to explode on their own unless they are fiddled with,” Tiwary stressed.

In the wake if the incident, Jalpaiguri Police has issued an advisory urging people not to handle any suspicious objects flowing down the river.

"In light of the severe flooding in Sikkim, certain military equipment including firearms and explosives were carried by the Teesta River. We urge the public to be vigilant and report any unfamiliar objects, crates, packages, firearms or any suspicious items seen floating in the water to the nearest police station immediately, the advisory stated.

"Please refrain from handling these items in any manner, as they pose a potential risk of a dangerous explosion," the notice stated.

The Sikkim government, too, has urged people to remain careful if they ventured into the Teesta River basin as there could be explosives and ammunition lying under the muddy waters. "These ammunition should not be handled or picked up inadvertently as they could explode causing grievous injuries," the state Land Revenue & Disaster Management Department said in an advisory.

Local residents were directed to inform the district administration and other authorities if they came across explosive materials in the river basin.