The death toll rose to 19 in the fire that gripped a fireworks factory near Sattur in Tamil Nadu's Virudhunagar district following an explosion on Friday.
The explosion occurred when some chemicals were being mixed to produce fireworks at the unit in Acchankulam village, they said, adding the injured had been hospitalised.
The factory building was damaged badly under the impact of the explosion and many suffered burns.
Several fire fighting units were deployed to douse the fire and take up the rescue operations.
Earlier, TV visuals showed relatives of the victims wailing near the mishap site while the injured were rushed to hospitals in ambulances.
Such explosions while mixing chemicals in cracker manufacturing units have been reported in the past in Virudhunagar district, especially places in and around Sivakasi and Sattur, the national hub of fireworks.
In March last year, six people were killed and four injured in the factory at Sippiparai near Sattur when fire broke out due to friction when chemicals were being mixed for making the fireworks.
A similar blast at a fireworks factory in neighbouring Madurai district in October last year had claimed lives of seven women workers.
PM, CM express grief, announce ex-gratia
Prime Minister Narendra Modi, Tamil Nadu Chief Minister K Palaniswami, Governor Banwarilal Purohit, Congress MP Rahul Gandhi and DMK President M K Stalin were among those who condoled the deaths.
Modi and Palaniswami announced an ex-gratia of Rs two lakh each and three lakh each to the kin of the deceased from the Prime Minister's National Relief Fund and the Chief Minister's Public Relief Fund respectively.
Palaniswami said he has ordered a probe into the incident, while assuring due legal action.
Modi on Friday said the "fire at a firecracker factory in Virudhunagar, Tamil Nadu is saddening."
Posting in his official Twitter handle, @PMO India, he said "in this hour of grief, my thoughts are with the bereaved families. I hope those injured recover soon.
Authorities are working on the ground to assist those affected: PM @narendramodi."
"An ex-gratia of Rs 2 lakh each has been approved from PMNRF for the next of kin of those who have lost their lives due to a fire in Virudhunagar, Tamil Nadu. Rs 50,000 would be given to those seriously injured," he said, in tweet, which was also made in Tamil.
Palaniswami expressed grief over the deaths.
"I was anguished to know that 36 persons have been injured in the explosion and have directed the officials to ensure due medical treatment to them," he said in the statement.
He announced a sum of Rs three lakh each to the families of the deceased and Rs one lakh to those who had suffered grievous injuries.
The Chief Minister said he has directed expediting the relief work and asked the district collector Virudhunagar to console the families of the victims in person.
The collectors concerned should conduct periodic checks at such units to ensure workers' safety, he said, adding the factories should follow due safety measures in view of the coming summer season, indicating high temperatures then could lead to similar mishaps.
Purohit said he was shocked and grieved to hear about the accident and prayed for the early and complete recovery of the injured.
"I offer my deep condolences to the families of those who are mourning the loss of their near and dear ones," he said in a Raj Bhavan statement.
Expressing grief over the incident, Stalin called for adequate relief to the families of the deceased and due medical attention to the injured.
Gandhi, in a tweet, said: "Heartfelt condolences to the victims of the firecracker factory fire in Virudhunagar, Tamil Nadu. It's heart wrenching to think of those still trapped inside. I appeal to the state government to provide immediate rescue, support & relief," he added.
(With PTI inputs)