At least 19 youths were killed in a schoolgirls' dormitory blaze in Guyana, officials said Monday, with anger growing in the tiny South American country over the tragedy.

It is not yet known how the fire started Sunday in a dormitory housing girls aged 11-12 and 16-17, a person who helped the emergency services said under condition of anonymity.

The building was gutted by the inferno.

"Fourteen youths died at the scene, while five died at the Mahdia District Hospital," said the fire department in a statement.

The government had previously said 20 people died in the blaze at the Mahdia Secondary School in central Guyana.

Guyana, with a population of 800,000, is the only English-speaking country of South America. It is a former Dutch and British colony which recently discovered it holds the world's largest per capita oil reserves.

After the weekend tragedy, more than a dozen children received hospital treatment locally while six serious cases were airlifted to the capital Georgetown.

"Two children remain in critical condition, while four are nursing severe injuries as a result of the incident," added the fire brigade.

There were 63 pupils inside the building when the fire broke out.

"This is a major disaster. It is horrible, it is painful," President Irfaan Ali said on Sunday night.

Ali said he had ordered arrangements to be made in Georgetown's two major hospitals "so that every single child who requires attention be given the best possible opportunity to get that attention." 

- 'Pain, agony, trauma' -

On Monday, around 50 relatives and friends of the fire victims demonstrated in Chenapau, a village close to Mahdia that is home to many of the school's pupils.

"The sheer pain, the agony, the trauma. Who will be held responsible?" Michael McGarrell, who lost two nieces in the blaze, asked AFP by telephone.

Protesters held up banners demanding justice and compensation, and criticizing the fact that the dormitory had barred windows.

"Why are school children grilled up in death traps? What are we going to tell the parents?" said McGarrell, an activist with the Amerindian People's Association (APA) that is often at odds with the government over land rights.

"Firefighters did manage to rescue some 20 students by breaking holes in the north-eastern wall of the building," the fire service said in its statement.

Private and military planes have been sent to Mahdia, located about 200 kilometers (125 miles) south of Georgetown, as the region is affected by heavy rains.

"Five planes have already taken off to Mahdia to support the regional health officials with additional medical supplies and medivacs," the government statement said.

At least one plane with three evacuees arrived back in Georgetown, according to an AFP journalist. 

The government said officials were supporting efforts at Ogle airport in the capital to "receive the critical patients and coordinate an emergency plan of action."

"A full-scale medical emergency action plan has been launched," it added.

Natasha Singh-Lewis, an opposition MP, called for an investigation into the fire's cause.

"We need to understand how this most horrific and deadly incident occurred and take all necessary measures to prevent such a tragedy from happening again," she said.

Among the poorest nations in South America, Guyana hopes the discovery of oil will help spur development. The country also boasts the second-highest percentage of forest cover on earth.

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