WASHINGTON _ The United States and its allies are beefing up their firepower in Afghanistan with fresh troops and heavily armored attack jets in anticipation of an al-Qaida and Taliban guerrilla offensive that is expected this spring.
The moves suggest that the coalition forces are preparing for a new phase of the war, in which enemy fighters are likely to stage hit-and-run attacks designed to offset Western technological advantages and exploit weaknesses in U.S. and allied intelligence-gathering.
The new strategy is based on lessons learned in the last major ground offensive, Operation Anaconda, the mountain battle last month in which eight Americans and three Afghans were killed.
A force of 1,700 British Royal Marine commandos was scheduled to arrive in Afghanistan by week's end, joining about 13,000 American and allied troops who were already there.
A small squadron of A-10 "Warthog" jets, renowned for their ability to deliver a devastating amount of fire on ground targets as well as to sustain heavy damage themselves, have been stationed at Bagram Air Base, north of Kabul, for the first time in the 6-month-old war. "The introduction of the 1,700 British ground forces and the A-10 aircraft, I think, is an indication that this is going to be a less technology-intensive, more manpower-intensive part of the conflict," said Andrew Krepinevich, executive director of the Center for Strategic and Budgetary Assessments, a Washington research center.
In Operation Anaconda, inadequate intelligence failed to identify the strength and disposition of enemy forces, high altitude taxed the ability of U.S. troops to fight effectively and attack helicopters proved vulnerable to ground fire from well-entrenched enemy fighters.
The United States now probably will "err on the side of bringing in too much as opposed to too little when it comes to ground forces and air cover," Krepinevich said.
The A-10s, armed with 30 mm Gattling guns, plus Maverick and Sidewinder missiles, are a key part of that mission. The slow-moving aircraft can fly as low as 75 feet, making it particularly useful in providing cover for small units hunting for enemy fighters. Titanium armor encases the cockpit and parts of the flight-control system, making it difficult to damage.
Senior defense officials said the next operation also would include better surveillance of helicopter landing zones and preparatory artillery barrages to clear the area for troops. Partly as a result of the inadequate intelligence, none of the landing zones in Anaconda was cleared sufficiently by airstrikes or artillery barrages before U.S. troops arrived.
"When you're uncertain of the intelligence, which you usually are, the safe thing to do is blast the hell out of an LZ before you send a big helicopter into it," said a senior Pentagon official who spoke on condition of anonymity. "That didn't happen, partly because the fear was that the al-Qaida and the Taliban would run away. Instead, we got a couple of hot LZs that we didn't expect."
The deployment of the A-10s and the British troops comes as U.S. and coalition officials say small pockets of al-Qaida and Taliban fighters continue to gather in small groups in eastern Paktia province close to where Operation Anaconda took place.
In a Pentagon briefing last week, Air Force Brig. Gen. John W. Rosa Jr., the Pentagon's deputy director for operations, said enemy forces might begin to move more freely as snow melts in the high mountain passes of eastern Afghanistan.
U.S. and allied soldiers searching for the fugitive fighters have found and destroyed several large caches of weapons and ammunition, according to defense officials.
On Thursday, Rosa described the current operations as reconnaissance and intelligence-gathering missions carried out by small units of special operations and conventional troops.
"We are pacing when we attack and how we attack on our terms," he said. "And obviously, all those signs have not come together yet. They're still in the gathering mode before another operation takes place."
On Friday, Army Gen. Tommy Franks, commander of the war in Afghanistan, suggested that future allied operations in the region could consist of quick raids or large-scale attacks, depending on how intelligence develops on the movements and locations of enemy troops.
"When we seize upon an area where we identify enemy forces, then we will go in there and we'll clear it in a fashion that might look a lot like Anaconda, might be considerably smaller, could be larger," Franks said. "We just don't know."
Coalition troops have found pamphlets in eastern Afghanistan offering rewards for the death or capture of American and allied troops. Franks said the leaflets illustrate that "Afghanistan remains a very, very dangerous place" for allied forces.
One expert suggested that the British commandos, who specialize in cold-weather and high-altitude fighting, most likely would be used to help stop enemy fighters from infiltrating through the mountains along the border with Pakistan. The approach is more aggressive than waiting for large numbers of fighters to mass in a single place, as happened in Operation Anaconda.
"You can't just fight a ground war by reacting," said retired British Maj. Charles Heyman, editor of Jane's World Armies, an authoritative reference book. "What you have to do is get out and patrol.
"You have to create a situation as best you can where the Taliban and remnants of al-Qaida are frightened to move around in the mountains because they will get ambushed or they will have an airstrike or artillery strike called in on them."