The Pentagon plans to add nearly $20 million in high-tech sensors to Tunisia’s border, doubling down on US and European investments to stop migrants, extremists and drug traffickers from crossing from Libya.

Defense Department officials notified Congress of the move in a letter last month, drawing from a joint fund set up with Germany in September to secure Tunisia’s 300-mile border with Libya. Germany contributed funding that will be used specifically for the sensors.

“The funds will enhance the capacity of the government of Tunisia to detect and respond to threats posed by the trafficking of illicit materials,” Assistant US Secretary of Defense for Homeland Defense Kenneth Rapuano wrote in congressional correspondence reviewed by Al-Monitor.

The US Defense Threat Reduction Agency, a Pentagon office charged with countering weapons of mass destruction, kick-started a fence stretching along half of the Tunisian-Libyan border with a $24.9 million grant in 2016. Construction of the 125-mile barrier began less than a year after an attacker linked to the Islamic State (IS) gunned down 38 victims — most of them British tourists — near the resort town of Sousse on the Tunisian coast.