A growing number of Pakistani militants who earlier operated only inside Pakistan and Kashmir are joining the intensifying insurgency against U.S. and NATO forces in Afghanistan, U.S. officials say.
The fighters, who are taking part in increasingly sophisticated attacks on Western troops, include guerrillas hardened by years of combat against Indian forces and others from outside the Taliban strongholds in Pakistan's Federally Administered Tribal Areas, or FATA, the officials say.
They say the influx far outstrips the flow of other foreign fighters such as Arabs, Uzbeks and Chechens into the area and coincides with a drop in high-profile attacks in Pakistan that reached a climax last December with the assassination of former Prime Minister Benazir Bhutto.
Growing violence in Afghanistan, including a bombing at the Indian Embassy that killed 41 people and wounded 139 on July 7, has put new pressure on Pakistan to control militants and raised concern about possible links between militant groups and Pakistani intelligence agents.
The rise in the number of Pakistanis involved in the Afghan insurgency was confirmed by several U.S. officials, including senior military officers, who spoke on condition of anonymity because the topic involves classified intelligence.
"When we're talking about foreign fighters in Afghanistan, they're primarily Pakistanis," one official said.
"The number of Pakistani militants who previously focused inside Pakistan and are now operating in Afghanistan has increased, and that increasing number is a concern."
Officials declined to say how many Pakistanis were involved but said the smaller rise in militants from other countries probably amounts to a few hundred fighters.
A sharp rise in violence near Afghanistan's eastern border with Pakistan this year has strained U.S.-Pakistani relations and helped prompt the Pentagon to look for ways to speed additional troops to boost the 53,000-strong NATO force.
The United States has 34,000 troops in Afghanistan, including 15,000 operating as part of that NATO force.
NATO reported a 40 percent year-on-year jump in insurgent violence this spring in an area known to the military as Regional Command-East, across the border from Taliban and al Qaeda havens in Pakistan.
