WASHINGTON (Reuters) -- Violence has risen sharply this year along Afghanistan's eastern border with Pakistan, where a warm winter is allowing militants freer movement through mountain passes, a U.S. Army officer said.
Colonel John Johnson, commander of the 101st Airborne Division's 4th combat brigade, said militants from the Taliban, Al-Qaeda and other groups have also shifted the target of their attacks from U.S. and NATO forces to the Afghan army and police.
"Over this past year, there's been roughly a 20 percent increase in overall enemy activity. And over the past two months, compared to 2008, roughly about 30 percent," he told Pentagon reporters by video link from a base in Khost Province.
He did not disclose the number of attacks, but said "much of that increase has been in ineffective attacks."
Johnson commands a force of about 5,000 U.S. and coalition troops in an area that shares a 500-kilometer border with Pakistan's Federally Administered Tribal Areas, where U.S. officials say militants operate from safe havens. His area of operation encompasses Khost, Paktika, and Paktia provinces.
The increase in violence comes as U.S. and NATO commanders prepare for a further increase in militant attacks this spring.
President Barack Obama last month authorized the deployment of about 17,000 extra U.S. forces to Afghanistan to tackle the intensifying insurgency. Most of the extra U.S. troops are due to deploy to southern Afghanistan rather than the East.
There are about 38,000 U.S. troops in the country as part of a 70,000-strong Western military presence that includes NATO's International Security Assistance Force.
Johnson's unit is expected to leave Afghanistan this month. It will be replaced by a brigade from the army's 25th Infantry Division.