WASHINGTON (AP) — President Joe Biden on Sunday called for the release of U.S. Navy veteran Mark Frerichs, who was taken hostage in Afghanistan nearly two years ago.

Frerichs, a civil engineer and contractor from Lombard, Illinois, was kidnapped in January 2020 from the capital of Kabul. He is believed to be in the custody of the Taliban-linked Haqqani network.

“Threatening the safety of Americans or any innocent civilians is always unacceptable, and hostage-taking is an act of particular cruelty and cowardice,” Biden said in a statement to mark the second anniversary of the kidnapping Monday. “The Taliban must immediately release Mark before it can expect any consideration of its aspirations for legitimacy. This is not negotiable.”

The statement came as Afghanistan faces a thorny humanitarian crisis following the U.S. withdrawal in August. The Taliban quickly seized control of much of the country and the foreign aid that been flowing into the country largely halted, putting at risk the lives of millions of Afghans who could starve or freeze to death.

Charlene Cakora, Frerichs’ sister, issued a statement saying that her family is “grateful” for Biden’s words.

“But what we really want is to have Mark home,” she said. “We know the president has options in front of him to make that happen and hope Mark’s safe return will become a priority for him personally.”