US President Joe Biden speaks during a press briefing. File photo

US President Joe Biden on Sunday called on Afghanistan's Taliban rulers to release a US civil engineer, also US Navy veteran Mark Frerichs, who was abducted two years ago and is believed to be the last American hostage held by the Taliban.

Frerichs, a 59-year-old US Navy veteran from Lombard, Illinois, who worked in Afghanistan for a decade on development projects. He was kidnapped a month before the February 2020 US troop pullout deal was signed and was transferred to the Haqqani network, a brutal Taliban faction accused of some of the deadliest attacks of the war.

READ MORE

Syria intercepts Israeli missile barrage targeting Damascus

Imran welcomes Canadian PM condemnation of Islamophobia

Monday marks his second year in captivity.

"Threatening the safety of Americans or any innocent civilians is always unacceptable, and hostage-taking is an act of particular cruelty and cowardice,” President Joe Biden said in a statement to mark the second anniversary of the kidnapping on Monday.

"The Taliban must immediately release Mark before it can expect any consideration of its aspirations for legitimacy. This is not negotiable."

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.”