Hours after U.S. Defense Secretary Jim Mattis arrived in Afghanistan's capital for an unannounced visit Wednesday, militant fighters fired several rockets that exploded at or near Hamid Karzai International Airport in Kabul. No injuries have been reported.

Mattis is visiting Afghanistan along with NATO Secretary-General Jens Stoltenberg, to discuss security plans and training in the country.

NPR's Tom Bowman, who is traveling with Mattis, reports:

"Mattis said he would not abandon Afghanistan to what he called a merciless enemy that tried to kill its way to power. He said the only way ahead for the Taliban is a negotiated settlement.

"A new strategy announced by President Trump calls for some 4,000 more U.S. troops in Afghanistan to train Afghan forces; Mattis said the U.S. would work to expand the Afghan air force and special forces. Just before Mattis spoke, rockets slammed into the military section of Kabul airport."

Copyright 2017 NPR. To see more, visit http://www.npr.org/.