A record of almost 19,000 children have crossed the dangerous Darien Gap jungle between Colombia and Panama this year en route to the United States, the UN Children's Fund (UNICEF) said Monday.

That figure is "nearly three times more than the number registered over the five previous years combined," said UNICEF.

The report said almost 20 percent of the migrants crossing the jungle are children, and half of those are below the age of five.

The Darien Gap is one of the main routes for migrants heading from South America to the United States, but the jungle has been overrun by armed groups such as drug and people traffickers.

"The number of migrant children who cross the Darien Gap on foot has hit an all-time high," said UNICEF, adding that the jungle "is one of the most dangerous places for migrants attempting to reach North America."

"In this dense tropical forest, migrant families with children are particularly exposed to violence, including sexual abuse, trafficking and extortion from criminal gangs.

"Children who cross the Darien Gap are also at risk of getting diarrhea, respiratory diseases, dehydration and other ailments that require immediate attention."

A Haitian migrant girl is seen crossing the Darien Gap jungle between Colombia and Panama in September 2021 -- a record number of children have made the trek in 2021, UNICEF says A Haitian migrant girl is seen crossing the Darien Gap jungle between Colombia and Panama in September 2021 -- a record number of children have made the trek in 2021, UNICEF says Photo: AFP / Raul ARBOLEDA

Wild animals, insects and a lack of safe drinking water exacerbate the problems of trying to cross the jungle.

At least five children have been found dead in the jungle in 2021, while more than 150, including newborn babies, have arrived in Panama without their parents, a near 20-time increase over 2020.

"Each child crossing the Darien Gap on foot is a survivor," said Jean Gough, UNICEF regional director for Latin America and the Caribbean.

"Never before have our teams on the ground seen so many young children crossing the Darien Gap -- often unaccompanied."

He said the issue needs to be treated as a region-wide humanitarian crisis.

So far in 2021, more than 91,000 migrants have crossed the 575,000 hectares (1.4 million acres) of virgin jungle, according to Panama's migration authorities.

The majority of migrants tackling this treacherous journey are Haitians and Cubans, but some come from as far afield as Africa or Asia.