Hundreds of Afghan government troops prepared Sunday for a new offensive against Taliban (search) guerrillas who recently stepped up attacks in the south and east, including along on the border with Pakistan.

The planned offensive came amid a visit by U.S. Defense Secretary Donald H. Rumsfeld  (search), who told a joint news conference in Kabul  (search) with President Hamid Karzai (search) that the infiltration of terrorists into Afghanistan "is something that requires continuing attention."

"It's happening all across the globe. It proves the point that the global war on terror is not a problem in one country or for one country," Rumsfeld said.

A spate of attacks on Afghan police positions along the border and inland and heavy fighting in the past two weeks in a remote mountainous region of southern Zabul  (search) province have raised fresh doubts about the precarious grip Karzai has over parts of the country.

U.S. military spokesman Col. Rodney Davis said that more than 100 Taliban guerrillas have been killed in the fighting since Aug. 30 — centered on the Dai Chupan district of southern Zabul province. Four American troops have also been killed in the past month, one in Dai Chupan (search).

The latest raid on the insurgents came Saturday night and involved American aircraft, Davis said.

While the situation in Dai Chupan has calmed in recent days, Afghan officials say forces are still hunting Taliban believed to have moved to nearby areas.

Hundreds of Afghan troops have been sent to the town of Naubaghar, some 45 miles east of Qalat — the capital of Zabul province — to join another offensive against Taliban insurgents, said Ahmad Zia Masoud, a spokesman for the governor of neighboring Ghazni province.

"We have reports about many Taliban are in this area ... but we haven't launched our operation yet," Masoud said.

Dozens of U.S. troops in armored personnel carriers were also deployed in the area, he said.

There were fresh reports of fighting near the Pakistani border, where suspected Taliban insurgents attacked a police station. There were no casualties during the two-hour firefight late Saturday and early Sunday in Ziruk, in eastern Paktika province, said Sayed Khan, a police spokesman in the province.

Afghan officials say Taliban and Al Qaeda (search) fighters are hiding in Pakistan's border regions, but Pakistan says it is doing all it can to prevent that.

Speaking about security at the border, Karzai said Pakistani President Gen. Pervez Musharraf has promised "that everything will be done to stop terrorist activities to Afghanistan."

Pakistani troops recently deployed along the border, apparently to search for Al Qaeda and Taliban fugitives.

Earlier Sunday, Rumsfeld visited an 80-member team of U.S. troops stationed at Gardez in the east near the Pakistani border. They are among 11,500 coalition forces hunting for followers of terror groups in Afghanistan.

In Zabul, the scene of the recent heavy fighting against the Taliban, more than 300 tribal leaders met under a large tent to discuss ways to improve security — and improve relations between authorities and a local population that traditionally supports Islamic hard-liners.

"Taliban can not return here, they have no future here," Zabul Gov. Hafizullah Hashami said in a speech at the meeting held in the grounds of his residence in the provincial capital Qalat.

Elsewhere in southern Afghanistan, suspected insurgents fired a rocket late Saturday at the home of an intelligence official in the capital of Helmand province, seriously injuring him and his driver.

There was no claim of responsibility for the attack. The provincial intelligence chief blamed Taliban and fighters loyal to renegade warlord Gulbuddin Hekmatyar, an ally of Al Qaeda and the hardline Islamic guerrillas. U.S.-led forces drove the Taliban regime from power in 2001.