(CNN) At least 650 people died attempting to cross the US-Mexico border this year, more than any other year since an international agency began documenting deaths in 2014.
The International Organization for Migration -- the agency documenting the deaths -- didn't specify the reason for the deaths but crossing the US southern border is often a dangerous journey that over the years has resulted in deaths and rescues.
"The rising migrant death toll in the region is highly alarming," said Michele Klein Solomon, IOM Regional Director for Central and North America and the Caribbean, in a statement.
Arrests of migrants along the US southern border this year remained high, even during months when numbers usually dip, meaning that thousands were exposed to even more difficult elements.
US Customs and Border Protection has previously said a majority of migrant border deaths have been related to heat exposure. The agency recorded 557 southwest border deaths during fiscal year 2021. That's up from 254 deaths in fiscal year 2020 and 300 deaths in 2019, marking a significant increase amid a 30-year record year for border crossings.
There were also 12,854 Border Patrol rescues this past fiscal year, far surpassing the previous four years, which is as far back as the agency has tracked this data. The previous high was in 2019, with 5,335 rescues.
In June, when rescues were already spiking, CBP said smuggling organizations were abandoning migrants in remote and dangerous areas, leading to a dramatic rise in the number of rescues.
Since 2014, 5,755 people died while migrating across Central America, North America and the Caribbean, IOM found.