American troops on Afghanistan's eastern frontier have seen a tripling of attacks since a truce between the Pakistani army and pro-Taliban tribesmen that was supposed to stop cross-border raids by militants, a U.S. military officer said Wednesday.

Pakistan's Foreign Ministry rejected the U.S. claim and said home-based insurgents were behind the violence in Afghanistan, where at least 25 militants were reported killed in fighting Wednesday.

Raising further questions about the cease-fire, a Pakistani political leader maintained Taliban leader Mullah Omar approved the deal. A government official denied that.

CountryWatch: Afghanistan

The developments could add to the feuding between Afghan President Hamid Karzai and Pakistani President Pervez Musharraf, who were having dinner Wednesday night with President Bush at the White House to try to patch up their dispute over how to quell Islamic extremists.

The U.S. officer said the cease-fire that began June 25, cemented by the signing of a peace accord Sept. 5, contributed to the Taliban's resurgence in Afghanistan. He said ethnic Pashtun insurgents are no longer fighting Pakistani troops and are using Pakistan's North Waziristan border area as a command-and-control hub for attacks in Afghanistan.

Pakistani tribal elders brokered the truce between Musharraf's government and militants, which ended years of unrest in the tribal region bordering Afghanistan.

But the agreement appears to have bolstered Taliban infiltrators, with the number of attacks in eastern Afghan provinces rising threefold since July 31, said the U.S. officer, who agreed to discuss the situation only if not quoted by name due to the sensitivity of the issue.

"That's why they had the chance to rest and refit, because they were in a sanctuary," he said, referring to a surge in Taliban attacks over the last several months without giving specific numbers for incidents before or after the truce.

Insurgent bombings, ambushes and rocket attacks had surged this year even before the cease-fire. But an Associated Press count of casualties shows the number of slain Afghan police and soldiers jumped to 62 in August from 29 in July and the number of Afghan civilian dead rose to 49 from 33. Deaths in the U.S.-led coalition and the separate NATO force rose to 27 from 17.

Both the U.S. and NATO launched big offensives this month in response to insurgent attacks, claiming to have killed 640 militants.

Pakistan's Foreign Ministry rejected the U.S. officer's comments relating increased violence to the truce, insisting Afghan insurgents get no help from inside Pakistan.

"We don't agree with this. These are just excuses," Foreign Ministry spokeswoman Tasnim Aslam said. "Whatever is happening, it is deep inside Afghanistan and is not because of Pakistan."

Pakistan turned over several Taliban fighters to the Afghan government after the accord, Aslam added.

Pakistan's Foreign Minister Khurshid Kasuri wouldn't comment on the report by the unnamed officer which he hadn't seen, but he defended the truce saying "our attempt is to prevent the bulk of the Pashtuns from going to the sides of the extremists, so let's give it a chance."

The U.S. officer acknowledged that the truce, championed by Musharraf, is not the only factor behind Taliban attacks in Afghanistan's eastern Paktika, Khost and Paktia provinces.

The Army's 10th Mountain Division has been pressing its own offensive, Operation Mountain Fury, sparking firefights and bombings that otherwise might not have occurred, the officer said.

Meanwhile, Latif Afridi, a top official in Pakistan's Awami National Party, said he received a letter containing Taliban leader Mullah Omar's approval of the North Waziristan peace deal.

He said the letter also claimed Pakistani militants who back the Taliban in North Waziristan would fall under the command of Jalaluddin Haqqani, a front-line Taliban commander.

It was not immediately possible to verify Afridi's claims. Government spokesman Shah Zaman dismissed them as "baseless."

Since the U.S.-led offensive that ousted the Taliban in late 2001, many of Afghanistan's former rulers are thought to have found sanctuary across the border. Some 30 members of the Taliban's top leadership, including Omar and the group's 10- to 12-member Shura Council, are believed to be in Pakistan, mainly Quetta, Miran Shah and Peshawar, the U.S. officer said.

Musharraf has said Omar is not in Pakistan, and that he's more likely to be in his former powerbase of Kandahar in southern Afghanistan.

The U.S. officer said the Taliban's connections with Pakistan run so deep that wounded fighters seek treatment on the Pakistani side of the border and even carry their dead to Pakistan for burial.

Some of the suicide bombers in Afghanistan have been recruited in Pakistan, including a 17-year-old boy who blew himself up in front of a U.S. military convoy in Kabul this month, killing a bystander and wounding three American soldiers, Afghan police say.

The border region is also believed to harbor top al-Qaida fugitives Osama bin Laden and Ayman al-Zawahri, the U.S. officer said, discounting reports that bin Laden may have died from typhoid or that his trail has gone cold.

"No, I don't think he's dead. The overall assessment is that they're still in Pakistan," the officer said.

In Afghanistan on Wednesday, insurgents attacked an Afghan police checkpoint in southern Helmand province and "at least 25 insurgents" were killed in the ensuing clash with international troops, the NATO-led force said in a statement.

Three Italian soldiers attached to the NATO force and one civilian were wounded Wednesday when a roadside bomb hit their vehicle in the western Herat province, the Italian Defense Ministry said.

The attack was the latest in a spree of bombings in previously calm western Afghanistan, where NATO and Afghan officials have reported an increase in Taliban activity. Four Italian soldiers were wounded Sept. 8 by a roadside bomb in neighboring Farah province.