New York: The US-led military operation in Afghanistan is facing grave peril as stepped up efforts by Taliban insurgents to target supply convoys for NATO troops, have considerably shot up war costs, media reports said here today.

In addition to targeting supply convoys, insurgents in Afghanistan have blown up roads and bridges that were the centerpiece of US efforts to rebuild the nation after NATO troops helped drive out the Taliban from power in 2001, the paper said.

The seven-year-old US campaign in the war-torn country has taken a rough turn over the last year as suicide attacks have surged and Karzai'

s control over the countryside ebbed.

"The attacks in Afghanistan and Pakistan are part of the militants campaign to isolate the fragile US-backed government in Kabul, led by President Hamid Karzai," the Wall Street Journal said.

"There has been a pretty clear trend in the past couple of weeks to interdict our supply routes," Brig Gen Mark Milley, deputy commander for US forces at Bagram Air Base in Afghanistan, is quoted as saying.

About 90 per cent of US goods destined for Bagram, the main US military base in Afghanistan, make an eight-day journey from Pakistan s Karachi port through the Torkham border crossing into Afghanistan, according to US officials.

Source : PTI