At least 55 of the around 70 people on board were killed in the accident, which happened in the early hours of Monday, local time.

Rescuers struggled to recover the bodies from the creek into which the bus had plunged.

Guatemalan President Bernardo Arévalo has declared three days of national mourning for the victims of the crash, one of the deadliest road traffic accidents in the region for years.

The bus normally covered the route between San Cristóbal Acasaguastlán and Guatemala City, officials said.

On Monday it had reportedly left the village of San Antonio La Paz at around 04:00 local time.

About 30 minutes later, on the outskirts of Guatemala City, it plunged 20m (65ft) from a bridge into a creek carrying wastewater.

Photos from the scene show the bus, lying on its roof, wheels in the air, in the shallow water.

Local media said the bus had been full of students, commuters, and people on their way to the capital for medical appointments.

As news of the accident spread, worried relatives gathered at the foot of the bridge waiting for news of their loved ones.

One woman told Guatemalan news site La Hora that her 67-year-old husband had set off at four in the morning but had never made it to work.

Another woman had identified the body of her brother, who had been on board the bus.

Rescue workers said they had retrieved 53 bodies so far.

Two people who had been rescued alive from the wreck died in hospital, bringing the total number of dead to 55.

The 24-year-old driver is reportedly among those who died.

Eyewitnesses described seeing the vehicle crash into two cars before it hit the guardrail and fell into the precipice.

Investigators said they would check if the driver could have lost control due to a brake failure.

Guatemala’s communications minister, Miguel Díaz Bobadilla, told reporters the bus was around 30 years old but had a valid licence for carrying passengers.

Díaz Bobadilla added that officials were checking if it may have carried more weight than it should have.

Police are also investigating a gun they found on board the bus.

The discovery of the weapon has given rise to speculation in local media that the driver may have panicked or been injured when he was threatened with the gun.

The deputy director-general of Guatemala’s National Civil Police, Helver Beltetón, said the gun was registered to one of the deceased passengers, who worked as a private security guard.

Beltetón said that police were not “ruling out any hypothesis”.

He added that “the brakes could have failed but we’re also not ruling out an accident or a criminal act, all that will be investigated”.

A first group of 75 soldiers arrived on Friday and another 75 on Saturday, all drafted from the military police, according to Guatemala’s government.

A state of emergency has been in place across the Caribbean nation for months as the government battles violent gangs that have taken control of much of the capital Port-au-Prince.

The forces are in Haiti to boost a United Nations-backed security mission led by Kenya that has so far failed to prevent violence from escalating.

Kenya sent nearly 400 police officers in June and July last year to help combat the gangs.

This was the first tranche of a UN-approved international force that will be made up of 2,500 officers from various countries.

A small number of forces from Jamaica, Belize and El Salvador are also in Haiti as part of the mission and the US is the operation’s largest funder.

In March 2024, armed gangs stormed Haiti’s two biggest prisons, freeing around 3,700 inmates.

The Ouest Department – a region including Port-au-Prince – was originally put under a state of emergency on 3 March, after escalating violence gripped the capital.

Chronic instability, dictatorships and natural disasters in recent decades have left Haiti the poorest nation in the Americas.

In 2021, President Jovenel Moïse was assassinated by unidentified gunmen in Port-au-Prince.

Since then the country has been wracked by economic chaos, little functioning political control and increasingly violent gang warfare.

The children were taken into care on Friday when police raided a farm used by the Lev Tahor movement, which is under investigation in several countries for serious sexual offences.

Interior Minister Francisco Jimenez said they were allegedly being abused by a member of the sect.

But on Sunday, sect members broke into a care centre where they were being held in an attempt to get them back, leading to scuffles with police.

The Lev Tahor sect is known for extremist practices and imposing a strict regime on its followers.

It advocates child marriage, inflicts harsh punishments even for minor transgressions and requires women and girls as young as three years old to completely cover up with robes.

The sect accuses the Guatemalan authorities of religious persecution.The community settled in Mexico and Guatemala between 2014 and 2017. In 2022, members of the sect were arrested in a police operation in the southern Mexican state of Chiapas, but they were later freed for lack of evidence.

The events began when police raided the sect’s farm in Oratorio, south-east of Guatemala City, on Friday, taking the children into care.

Prosecutors said there were suspicions of “forced pregnancy, mistreatment of minors and rape”.

But two days later, about 100 of the children’s relatives – all members of the sect – gathered outside the centre where they were being held to call for their return.

Some sect members then forced open the gate and tried to abduct the children and adolescents sheltered there, the Attorney General’s Office said.

But the children were intercepted by the authorities and put into a white minibus, local media reported.

With police help, the centre “managed to locate and protect everyone again”, the Attorney General’s Office added.

Officials had previously tried to check on the children’s wellbeing, but were prevented from entering the farm by sect members.

Authorities estimate that the community is made up of about 50 families residing in Guatemala, the US, Canada and other countries.

The Jewish Community of Guatemala has issued a statement disowning the sect, describing it as foreign to its own organisation.

It expressed support for the Guatemalan authorities in carrying out necessary investigations “to protect the lives and integrity of minors and other vulnerable groups that may be at risk”.