The European Union's border agency, Frontex, has opened a new command center in Lisbon to coordinate operations and strengthen surveillance along the external borders of Spain and Portugal, the agency said Thursday.

With the deployment of EU officials, Frontex's coordination and command functions will be "moved closer to one of Europe's most important external borders," Frontex said.

"Portugal and Spain are key partners with their sea and land borders," said Frontex Director Hans Leijtens.

Frontex also noted that both Spain and Portugal have major airports with a high volume of arrivals from outside the EU.

Many migrants attempting to reach Spain risk their lives by crossing the Mediterranean from North Africa, often in unseaworthy vessels.

Thousands drown or disappear each year, according to official data, though accurate numbers are difficult to come by.

"The Central Mediterranean is the deadliest known migration route in the world," according to the U.N.-affiliated International Organization for Migration, which has recorded tens of thousands of deaths and disappearances since 2014.