While the investigation was ongoing, authorities did not say what may have started the fire.
Kuwait City, Kuwait: Kuwaiti authorities said Thursday three people had been detained for suspected manslaughter over a building fire that killed dozens of Indian foreign workers and plunged relatives and friends into mourning.
Three Filipinos were also among the 50 dead, officials in Manila said, after the fire sent black smoke billowing through the six-storey building south of Kuwait City.
Most of oil-rich Kuwait's population of more than four million is made up of foreigners, many of them from South and Southeast Asia working in construction and service industries.
The fire, which also injured dozens, broke out around dawn on Wednesday at the ground level of the block housing nearly 200 workers in the Mangaf area, heavily populated with migrant labourers.
"One of the injured died" overnight, Kuwaiti Foreign Minister Abdullah Al-Yahya told reporters, after 49 people were declared dead on Wednesday.
"The majority of the dead are Indians," he added. "There are other nationalities but I don't remember exactly."
Many of the dead and injured suffocated from smoke inhalation after being trapped in the building by the blaze, according to a source in the fire department.
One Kuwaiti and two foreign residents have been detained on suspicion of manslaughter through negligence of security procedures and fire regulations, the public prosecution service said.
While the investigation was ongoing, authorities did not say what may have started the fire.
On Wednesday, Interior Minister Sheikh Fahd Al-Yousef vowed to address "labour overcrowding and neglect", and threatened to close any buildings that flout safety rules.
Friends and relatives of the victims, who are among millions of Asians who live and work in the wealthy Gulf to remit money to their families, were in shock at the tragedy.
Shameer Umarudheen's "entire village is in mourning", said Safedu, a relative of the 33-year-old victim from Kollam, in the southern Indian state of Kerala.
"He was a lovely man. Always very friendly to everyone around," Safedu added.
"He does not come from a well-off family, so him going to Kuwait was a chance for the family to do better."
DNA testing
Reji Varghese said his close friend Lukose VO, 49, was staying on the sixth floor of the block. His death was reported by another worker who leapt from the second floor, breaking his leg, to escape.
"I'm still not able to come to terms with it. We didn't believe the news when we heard about it," said Varghese.
"I spoke to him just last week... This news is a shock."
On Wednesday, Prime Minister Narendra Modi promised help for those affected by the "gruesome fire tragedy", announcing Rs 2 lakh payments to next of kin.
Junior foreign minister Kirti Vardhan Singh has flown in to help survivors and organise the repatriation of remains on an Indian air force plane.
"Some of the bodies have been charred beyond recognition, so DNA tests (are) underway to identify the victims," he told Indian media.
In Manila, the Department of Migrant Workers said three Filipinos had died from smoke inhalation, with two more in critical condition while six escaped unharmed.
"We are in touch with the families of all the affected (migrants), including the families of those two in critical condition and the families of the three fatalities," Migrant Workers Secretary Hans Leo J. Cacdac said in a statement.
The blaze was one of the worst seen in Kuwait, which borders Iraq and Saudi Arabia and sits on about seven percent of the world's known oil reserves.
In 2009, 57 people died when a Kuwaiti woman, apparently seeking revenge, set fire to a tent at a wedding party when her husband married a second wife.
(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)