Taliban militants armed with rockets, grenades and automatic weapons abducted at least 400 students, staff and relatives driving away from a boy's school in a northwest Pakistani tribal region on Monday, police and a witness said.

The brazen abduction came amid rising militant violence in Pakistan's tribal belt — actions the military says are partly aimed at distracting it from its offensive against the Taliban in the nearby Swat Valley.

Police were negotiating with the Taliban via tribal elders to release of the captives taken in North Waziristan, said Mirza Mohammad Jihadi, an adviser to the prime minister. He said around 500 people were taken and that they were being held in the Bakka Khel area.

Details were still emerging late Monday about what happened, and much was murky.

Police official Meer Sardar said the abduction occurred about 20 miles from Razmak Cadet College in North Waziristan. The people were leaving the school area after they were warned to get out in a phone call from a man they believed to be a political official, Sardar said, citing accounts from a group of 17 who managed to get away.

Local media, however, reported that the group was leaving because their vacation had started.

Around 30 buses, cars and other vehicles were carrying the students, staff and others when they were stopped along the road by a large group of alleged militants in their own vehicles, according to a staff member at the school who was among those who escaped. The vehicle he was traveling in happened to be behind a truck on the road, and it was less visible, so the driver slipped away.

He requested anonymity out of fear of Taliban reprisal but said the school's principal was among those abducted.

The staffer said the assailants carried rockets, Kalashnikovs, hand grenades and other weapons. He estimated around 400 captives were involved.

It was unclear how many were students, though they made up the majority of the group. Cadet colleges in Pakistan are usually run by retired military officers and educate teenagers. They also typically provide room and board.

Late Monday, reports were coming in that at least one other bus managed to get away and reach a police station. Jihadi said at least 29 students escaped, apparently in addition to the 17 at Sardar's police station in the Marian area.

North and South Waziristan are major Al Qaeda and Taliban strongholds bordering Afghanistan.

Clashes over the past three days in South Waziristan have killed at least 25 militants and nine soldiers. In the latest attack, reported by the army Monday, militants fired rockets at troops, killing two.

The fresh fighting is fueling speculation that a month after re-igniting its battle against Taliban militants in Swat, the military will widen the offensive to South Waziristan. But army spokesman Maj. Gen. Athar Abbas said that for now, troops on the ground were simply reacting to attacks, not opening a new front.

"This is all to divert attention," Abbas said.

With its hands full in Swat, opening a front in South Waziristan now would be risky for the military.

Known for its harsh terrain, reticent tribes and porous border with Afghanistan, as well as its history of limited federal government oversight, South Waziristan would likely be a stiffer test for Pakistan's armed forces than Swat. The region also is the main base for Pakistani Taliban chief Baitullah Mehsud.

However, the U.S. and other Western nations who have praised Pakistan's strong-armed tactics in Swat would likely not want South Waziristan to stay untouched. It's the tribal regions, after all, where Al Qaeda and the Taliban have their key bases from which they plan attacks on Western forces across the border in Afghanistan.

The tribal areas also are the rumored hideouts of Al Qaeda leader Usama bin Laden and his deputy Ayman al-Zawahiri.

Asked about a timeframe for clearing the area, Abbas simply replied, "A plan to go or not to go into South Waziristan — shouldn't that be a highly classified matter?"

The army spokesman said major towns and cities in the Swat Valley will likely be cleared of Taliban fighters in a matter of days. It has already recaptured Mingora, Swat's main urban center. But many of the estimated 4,000 militants in the valley are believed to have fled to the hillsides, and Abbas said clearing those rural areas could require months more work.

One other problem with tackling South Waziristan now is that it would exacerbate an already massive humanitarian challenge facing the country — that of up to 3 million people displaced by the fighting so far. Already, large numbers of families have begun leaving South Waziristan amid rumors of an imminent operation.

Journalists have limited access to the tribal belt and Swat, making it difficult to independently verify information provided by the Pakistani military or other sources.

Militants, including Mehsud loyalists, have threatened and carried out some revenge attacks over the Swat operation in major Pakistani cities, including an assault on police and intelligence agency offices in the eastern city of Lahore that left 30 dead.

On Monday, a blast at a busy bus terminal in Kohat town, an area near the tribal regions, killed at least two people and wounded at least 18 others, said local police officer Zafarullah Khan.