Officials said today that they had no information indicating that Osama bin Laden is in Pakistan and took issue with reports that U.S. and Pakistani forces had launched a major new military operation to capture the fugitive al Qaeda leader.

"This is totally false, and we don't know where Osama is," Information Minister Rashid Ahmed told reporters. "The people who have given this statement are totally wrong. We don't know anything. He is not in Pakistan."

Rashid's statement followed media reports that Pakistani and U.S. forces had stepped up their search for bin Laden on the basis of intelligence gleaned from the arrest last Saturday of a top al Qaeda lieutenant, Khalid Sheik Mohammed.

Both here and in Washington, rumors continued to suggest that bin Laden's arrest may be imminent. This evening, a top official in the southwest Pakistani province of Baluchistan announced that U.S. and Afghan forces operating in neighboring Afghanistan had captured two of bin Laden's sons -- a claim that was promptly denied in Washington and later by Pakistani officials.

The confusion is partly a reflection of Pakistani political sensitivities. Although officials were happy to claim credit for the arrest of Mohammed, considered the third-ranking leader of al Qaeda, they are reluctant to dwell too heavily on their close cooperation with the United States, whose presence in the country is widely resented.

Pakistani officials have always insisted, for example, that FBI and CIA personnel in the country are limited to providing support, such as electronic surveillance, for Pakistani troops and intelligence agents in the vanguard of the search for bin Laden and other al Qaeda fugitives.

"In the basic agreement between Washington and Islamabad on cooperation against terror, there is no room for joint military action against suspected terrorist targets in Pakistan," a senior Pakistani military official in Rawalpindi said today. "The responsibility to combat terrorism within the territorial limits of Pakistan rest exclusively with Pakistani security forces."

Mindful of their delicate position here, U.S. officials do not dispute Pakistan's characterization of their secondary role. But they also have said the arrest of Mohammed in Rawalpindi yielded an evidentiary bonanza -- including computer disks and documents -- that could lead them to bin Laden if acted upon quickly, before the leads grow stale.

Over the past several days, Pakistani media have been filled with reports of stepped-up search activities, some allegedly involving U.S. military forces, in the remote region bordering Afghanistan where bin Laden has long been thought to have taken refuge. For example, a front-page story today in an English-language newspaper, the News, cited reports of U.S. helicopters landing "commandos" in a remote area of Baluchistan on Wednesday. Other U.S.-Pakistani military operations have been reported near the city of Chitral in the North-West Frontier Province.

Pakistan's president, Gen. Pervez Musharraf, told CNN in an interview aired today that while Pakistani intelligence agents were pursuing leads throughout the country, he doubted bin Laden was in Pakistan. "He seems to be alive," Musharraf told the network, adding: "He would be moving with a large number of bodyguards. He can't be in Pakistan."

As if to drive home the point, Baluchistan home minister Sanaullah Zehri told Pakistan's Geo television that U.S. and Afghan troops had killed seven al Qaeda members in a part of Afghanistan near the Pakistan border and that two of bin Laden's sons had been captured. But U.S. officials denied the claim, as did Musharraf's spokesman, Maj. Gen. Rashid Qureshi. "No one knows anything about this," Qureshi said.

Special correspondent Kamran Khan in Karachi, Pakistan, contributed to this report.

U.S. leaflets airdropped into Pakistan and Afghanistan offer a $25 million reward for Osama bin Laden's capture.