The U.S. military is sending a contingent of heavily armored battle tanks to Afghanistan for the first time in the nine-year war, defense officials said, a shift that signals a further escalation in the aggressive tactics that have been employed by American forces this fall to attack the Taliban.

The deployment of a company of M1 Abrams tanks, which will be fielded by the Marines in the country's southwest, will allow ground forces to target insurgents from a greater distance - and with more of a lethal punch - than is possible from any other U.S. military vehicle. The 68-ton tanks are propelled by a jet engine and equipped with a 120mm main gun that can destroy a house more than a mile away.

Despite an overall counterinsurgency strategy that emphasizes the use of troops to protect Afghan civilians from insurgents, statistics released by the NATO military command in Kabul and interviews with several senior commanders indicate that U.S. troop operations over the past two months have been more intense and have had a harder edge than at any point since the initial 2001 drive to oust the Taliban government.

The pace of Special Operations missions to kill or capture Taliban leaders has more than tripled over the past three months. U.S. and NATO aircraft unleashed more bombs and missiles in October - 1,000 total - than in any single month since 2001. In the districts around the southern city of Kandahar, soldiers from the Army's 101st Airborne Division have demolished dozens of homes that were thought to be booby-trapped, and they have used scores of high-explosive line charges - a weapon that had been used only sparingly in the past - to blast through minefields.

Some of the tougher methods, particularly Special Operations night raids, have incensed Afghan President Hamid Karzai, who told The Washington Post last week that the missions were undermining support for the U.S.-led war effort. But senior U.S. military officials involved in running the war contend that the raids, as well as other aggressive measures, have dealt a staggering blow to the insurgency.

The officials, who spoke on the condition of anonymity because they were not authorized to discuss specific tactics, said the combination of the raids, the airstrikes and the use of explosives on the ground have been instrumental in improving security in areas around Kandahar, a Taliban stronghold that has been the focus of coalition operations this fall.

"We've taken the gloves off, and it has had huge impact," one of the senior officials said.

That, in turn, appears to have put U.S. Army Gen. David H. Petraeus, the top coalition commander, in a much stronger position heading into a Friday meeting of NATO heads of state in Lisbon, where Afghanistan will be a key topic of discussion. It also will help the general make his case that the military's strategy is working when President Obama and his advisers conduct a review of the war next month.

A U.S. officer familiar with the decision said the tanks will be used initially in parts of northern Helmand province, where the Marines have been engaged in intense combat against resilient Taliban cells that typically are armed with assault rifles, rocket-propelled grenades and homemade bombs. The initial deployment calls for about 16 tanks, but the overall number and area of operations could expand depending on needs, the officer said.

"The tanks bring awe, shock and firepower," the officer said. "It's pretty significant."

Although the officer acknowledged that the use of tanks this many years into the war could be seen as a sign of desperation by some Afghans and Americans, he said they will provide the Marines with an important new tool in missions to flush out pockets of insurgent fighters. A tank round is far more accurate than firing artillery, and it can be launched much faster than having to wait for a fighter jet or a helicopter to shoot a missile or drop a satellite-guided bomb.

"Tanks give you immediate, protected firepower and mobility to address a threat that's beyond the range" of machine guns that are mounted on the mine-resistant trucks that most U.S. troops use in Afghanistan, said David Johnson, a senior researcher at the Rand Corp. who co-wrote a recent paper on the use of tanks in counterinsurgency operations.