Forward Operating Base Salerno, Afghanistan — In the enveloping darkness of a starless summer night, the sizzle-thump of incoming Taliban rockets is swiftly answered by the percussive boom of outgoing U.S. artillery. But the American troops manning this base in eastern Afghanistan know that their elusive nighttime foe can slip away to sanctuary in Pakistan, just 20 miles away.
The militants firing rockets at this installation, informally known as Camp Salerno, in all likelihood traveled here from Pakistan's tribal areas, home turf of several major Taliban commanders and their militias. The flow of fighters and arms into Afghanistan from Pakistan -- and the tribal belt's use as a fighter haven -- has long been a key concern of U.S. and other Western officials.
During a visit to the region last week, U.S. national security advisor James L. Jones Jr. urged Pakistan to press ahead with a long-delayed army offensive against Taliban fighters who had become entrenched in the country's northwest.
So far, though, the Pakistani military campaign has been centered on the Swat Valley, far from the border zone, and the tribal areas remain a wellspring of insurgent activity: suicide attackers, placers of roadside explosive devises, packers of vehicle bombs.
The frontier itself remains a magnet for violence; this week, a suicide attacker struck a crossing at Torkham, a major gateway into Afghanistan, killing a policeman, wounding several civilians and setting the checkpoint ablaze.
American commanders, however, believe a greater concentration of U.S. and Afghan troops in the border region is beginning to change the equation. The "battle space" overseen from Camp Salerno -- the Afghan provinces of Khowst, Paktia and Paktika -- now contains more U.S. forces than at any point during the nearly 8-year-old war. Troop increases ordered by the Obama administration will bring American forces in Afghanistan to a record 68,000 by year's end.
The mandate to give chase to the insurgents, at least using Western ground troops, stops at the rugged, mountainous border. Just across from Khowst and Paktika lie two of the most insurgent-plagued of Pakistan's tribal areas, North and South Waziristan.
Pakistani army commanders, after years of looking the other way while militants had free rein in the tribal areas, are in the early stages of what is billed as a major assault on South Waziristan, the redoubt of the leader of the Pakistani Taliban, Baitullah Mahsud.
