US-led troops in Afghanistan say they have begun a second major operation against suspected extremists.
The US says it has found several weapons caches
US spokesman Colonel Roger King said Operation Desert Lion began on Thursday with an aerial operation between the capital, Kabul and the US air base at Bagram.
US-led forces have been conducting Operation Valiant Storm since last week, in south-eastern Afghanistan.
Both operations are aimed at remnants of Osama bin Laden's al-Qaeda network, the Taleban and their supporters.
"Operation Desert Lion kicked off yesterday when coalition task force 82 conducted an air assault into the Koh-i-Safi mountains," Colonel King told journalists at Bagram.
Colonel King said two caches of weapons had been found, including 107mm rockets, mortar rounds and machine gun ammunition, the AFP news agency reports.
So far no-one has been arrested in the operation.
The Americans say Operation Valiant Storm has led to nine arrests as well as the discovery of a number of weapons hauls.
It is focussed on the Sami Ghar mountain range.
Some 600 troops are involved, using heavily-armed helicopters.
Valiant Strike has seen a combination of air assaults and land offensives.
It began on 20 March shortly after an attack on US troops in a mountainous ravine.
Troops have since been sweeping the area, conducting "village clearing" operations, trying to collect intelligence and identifying potential rebel hide-outs.
They are also seeking loyalists of local renegade warlord Gulbuddin Hekmatyar, whom the US has branded a terrorist.
US officers deny the operation was timed to coincide with the US-led attack on Iraq.
"This sends a really powerful message that we're not backing off in Afghanistan that we're fully capable of full-spectrum large combat operations," one spokesman said.