The new troops are the first wave of a surge of reinforcements expected this year. The process began to take shape under President George Bush but has been given impetus by President Barack Obama's call for an.
U.S. commanders have been contemplating sending up to 30,000 more soldiers to bolster the 33,000 already here, but the new administration is expected to initially approve only a portion of that amount. White House press secretary Robert Gibbs said Monday the president would decide soon.
The new unit - the 3rd Brigade Combat Team of the 10th Mountain Division - moved into Logar and Wardak provinces last month, and the soldiers from Fort Drum, N.Y., are now stationed in combat outposts throughout the provinces.
Militants have attacked several patrols with rifles and rocket-propelled grenades, including one ambush by 30 insurgents, Lt. Col. Steve Osterhozer, the brigade spokesman, said.
Several roadside bombs also have exploded next to the unit's MRAPs - mine-resistance patrol vehicles - but caused no casualties, he said.
"In every case our vehicles returned with overwhelming fire," Ostehozer said. "We have not suffered anything more than a few bruises, while several insurgents have been killed."
Commanders are in the planning stages of larger scale operations expected to be launched in the coming weeks.
Militant activity has spiked in Logar and Wardak over the last year as the resurgent Taliban has spread north toward Kabul from its traditional southern power base. Residents say insurgents roam wide swaths of Wardak, a mountainous province whose capital is about 35 miles from Kabul.
The region has been covered in snow recently, but Col. David B. Haight, commander of the 3rd Brigade, said last week that he expects contact with insurgents to increase soon.
"The weather has made it so the enemy activity is somewhat decreased right now, and I expect it to increase in the next two to three months," Haight said at a news conference.
Haight said he believes the increase of militant activity in the two provinces is not ideologically based but stems from poor Afghans being enticed into fighting by their need for money. Quoting the governor of Logar, the colonel called it an "economic war."
Afghan officials "don't believe it's hardcore al Qaeda operatives that you're never going to convert anyway," Haight said. "They believe that it's the guys who say, 'Hey you want $100 to shoot an RPG at a Humvee when it goes by,' and the guy says, 'Yeah I'll do that, because I've got to feed my family."'
Still, Haight said there are hardcore fighters in the region, some of them allied with Jalaludin Haqqani and his son Siraj, a fighting family with a long history in Afghanistan. The two militant leaders are believed to be in Pakistan.
Logar Gov. Atiqullah Ludin said at a news conference alongside Haight that U.S. troops will need to improve both security and the economic situation.
"There is a gap between the people and the government," Ludin said. "Assistance in Logar is very weak, and the life of the common man has not improved."
Ludin also urged that U.S. forces be careful and not act on bad intelligence to launch night raids on Afghans who turn out to be innocent.
It is a common complaint from Afghan leaders. President Hamid Karzai has long pleaded with U.S. forces not to kill innocent Afghans during military operations and says he hopes to see night raids curtailed.
Pointing to the value of such operations, the U.S. military said Monday that a raid in northwest Badghis province killed a feared militant leader named Ghulam Dastagir and eight other fighters.
Other raids, though, have killed innocent Afghans who were only defending their village against a nighttime incursion by forces they didn't know, officials say.
"We need to step back and look at those carefully, because the danger they carry is exponential," Ludin said.
Haight cautioned last week that civilian casualties could increase with the presence of his 2,700 soldiers.
"We understand the probability of increased civilian casualties is there because of increased U.S. forces," said the colonel, who has also commanded Special Operations task forces in Afghanistan and Iraq. "Our plan is to do no operations without ANA (Afghan army) and ANP (Afghan police), to help us be more precise."
The U.S. military and Afghan Defense Ministry announced last week that Afghan officers and soldiers would take on a greater role in military operations, including in specialized night raids, with the aim of decreasing civilian deaths.
The presence of U.S. troops in Wardak and Logar is the first time such a large contingent of American power has been so close to Kabul, fueling concerns that militants could be massing for a push at the capital. Haight dismissed those fears.
"Our provinces butt up against the southern boundary of Kabul and therefore there is the perception that Kabul could be surrounded," Haight said. "But the enemy cannot threaten Kabul. He's not big enough, he's not strong enough, he doesn't have the technology. He can conduct attacks but he can't completely disrupt the governance in Kabul."