At least 650 people died trying to cross the US-Mexico border last year, the highest number since records began in 2014.

The data compiled by the International Organization for Migration (IOM) – the UN’s migration agency – shows more than 200 deaths occurred along the border in Arizona.

The figure has emerged as US border patrol officers continue to use the pandemic-era protocol Title 42, which sends most migrants

Refugee rights advocates say that policy and other deterrence measures, along with the high number of people arriving at the border, is driving deaths and injuries up.

The rising migrant death toll in the region is highly alarming,” said Michele Klein Solomon, IOM’s Regional Director for Central and North America and the Caribbean, in a statement.

Arrests of migrants along the US southern border have remained high this year, 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 exceeding the previous four years. The previous high was in 2019, with 5,335 rescues.

The data from the US-Mexico border are part of IOM’s Missing Migrants Project, an initiative implemented in 2014 to document deaths and disappearances of people in the process of migration towards an international destination.

The project records incidents in which migrants, including refugees and asylum-seekers, have died at state borders or in the process of migrating to an international destination.

It was developed in response to disparate reports of people dying or disappearing along migratory routes around the world, and particularly in the wake of two shipwrecks in October 2013, when at least 368 people died near the Italian island of Lampedusa.

The project is also a concerted effort towards informing the Global Compact on Migration’s Objective 8, which commits signatory states to “save lives and establish coordinated international efforts on missing migrants.”

More than 40,000 people have lost their lives during unsafe migration journeys since 2014.

The IOM says data collected by Missing Migrants Project bear witness to one of the great political failures of modern times. The organisation has called for immediate safe, humane and legal routes for migration.