WASHINGTON - The rapid U.S. build up in the Afghan war will include more terrorist-hunting forces to chase down militants deemed too extreme to change sides, a top U.S. general disclosed yesterday.

"There's no question you've got to kill or capture those bad guys that are not reconcilable," Gen. David H. Petraeus, chief of U.S. Central Command, told the Senate Foreign Relations Committee. "And we are intending to do that."

In his first congressional testimony on President Obama's announced plan to send an additional 30,000 troops to Afghanistan, Petraeus also cautioned that progress against the insurgents probably will be slower than during the buildup of U.S. forces in Iraq two years ago and that the war will be "harder before it gets easier."

Petraeus said that in addition to an effort to "reintegrate" Taliban and other insurgents into mainstream Afghan society, there will be a harder push to eliminate the most hard-core extremists.

"In fact, we actually will be increasing our counterterrorist component of the overall strategy," he said. He provided no details beyond saying that additional "national mission force elements" would be sent to Afghanistan next spring.

He appeared to be referring to classified units, such as the Army's Delta Force, that specialize in counterterrorism and that have been used extensively in Iraq and Afghanistan. Gen. Stanley McChrystal, who now oversees the Afghan war and is scheduled to testify today before a House committee, previously headed those units in Iraq and Afghanistan.

Much of yesterday's Senate hearing focused on the link between instability in Afghanistan and the presence of the Taliban, al-Qaeda, and other extremist groups in neighboring Pakistan. Sen. Richard Lugar (R., Ind.) said he was confident that allied forces would improve security in Afghanistan, but that the biggest question is whether that would root out Taliban and al-Qaeda havens across the border in Pakistan.

"The risk is that we will expend tens of billions of dollars fighting in a strategically less important Afghanistan, while Taliban and al-Qaeda leaders become increasingly secure in Pakistan," Lugar said.

Patraeus responded that Pakistan's stepped-up efforts has been the most effective it has undertaken against internal extremists. That, he said, is "an important step forward."

As for Afghanistan, Petraeus forecast an increase in bloodshed next summer. He cited a combination of heightened U.S. and NATO military operations against the Taliban and increased turmoil resulting from Afghan government actions to combat corruption.

Petraeus, who executed the Iraq surge in 2007, said he supports Obama's revamped strategy, but he did not explicitly predict it would succeed. He called success "attainable." But in his less-than-rosy assessment, he called Afghanistan "no more hopeless than Iraq" when he got there in early 2007.

In Kabul yesterday, a top U.S. military officials said that a recent pay increase for Afghan soldiers and police appears to have resulted in a surge of new applicants.

Lt. Gen. William Caldwell, citing Afghan statistics, said 2,659 Afghans had applied to join the security forces in the first seven days of this month, about half of the month's recruiting objective. In the three previous months, recruiting fell short of targets, with only 830 applicants in September, he said.

Obama's strategy for Afghanistan depends heavily on rapidly growing a well-trained Afghan force that can begin to take over security from U.S. and NATO forces.

This article contains information from the Washington Post.