US Defense Secretary Mattis and NATO chief Stoltenberg in Kabul

KABUL: US Defense Secretary Jim Mattis arrived in Kabul Wednesday, an AFP reporter said, along with NATO chief Jens Stoltenberg weeks after Donald Trump´s pledge to send more troops to the war-torn country.

Mattis is the first member of the US president´s cabinet to visit Afghanistan since the strategy announcement to keep American boots on the ground there indefinitely.

The unnanounced high-level visit comes as Afghan security forces struggle to beat back the Taliban, which has been on the offensive since the withdrawal of US-led NATO combat troops at the end of 2014.

The resurgent militants have promised to turn Afghanistan into a "graveyard" for foreign forces and have been mounting deadly attacks as they maintain control over large swathes of the country.

US generals have for months been calling the situation in Afghanistan a "stalemate", despite years of support for Afghan partners, continued help from a NATO coalition and an overall cost in fighting and reconstruction to the United States of more than $1 trillion.

The war turns 16 next month, and is America´s longest-ever conflict.