U.S. Secretary of State Hillary Rodham Clinton walks beside Pakistani Foreign Minister Shah Mehmood Qureshi at the Iqbal Memorial in Lahore on Thursday. Clinton is on a three-day state visit to Pakistan. (Mansoor Ahmed/Associated Press)

U.S. Secretary of State Hillary Clinton defended the Pakistan government's aggressive campaign against extremist forces within its own borders, telling a group of Lahore university students that inaction was not an option.

"If you want to see your territory shrink, that's your choice," she told a crowd at the Government College of Lahore, where she was visiting as part of an effort to ease rising anti-American sentiment in Pakistan over the U.S. role in the campaign against insurgents in the country's tribal regions.

Clinton was responding to a student who suggested the U.S. was compelling the Pakistani government to attack its own territory. Clinton said inaction would lead to Taliban forces expanding their territory.

She likened the situation to a theoretical invasion from Canada to the United States.

It would be unthinkable, she said, for the U.S. government to decide, "Let them have Washington [state]" first, then Montana, then the sparsely populated Dakotas, because those states are far from the major centres of population and power on the East Coast.

Clinton said her three-day stay in Pakistan was to reach out to ordinary citizens and urge more effort to creating understanding between the U.S. and Pakistan.

Attack in Peshawar kills 105

She was able scheduled to meet Pakistan's army and security chiefs on Thursday, where she was expected to discuss Pakistan's military offensive in South Waziristan as well as the U.S. efforts in Afghanistan against Taliban forces.

The U.S. is also known to have been aiding Pakistan's fight though the employment of drone aircraft against extremist targets on the Pakistan side of the Afghan border, although neither government has officially acknowledged this.

Clinton, speaking to the students in Lahore, did not discuss the attacks, which have drawn criticism after reportedly leading to civilian deaths in some cases.

The secretary of state was only a few hours into her visit to Pakistan on Wednesday when a car bomb exploded at a popular women's market in the northwestern city of Peshawar, killing 105 people in the worst attack since 2007.

Three bombs have exploded in Peshawar this month. No group has claimed responsibility for Wednesday's attack, but the Taliban have warned Pakistan that they would stage attacks if the army does not end its offensive in South Waziristan, where the military has dispatched some 30,000 troops to flush out insurgents.

Clinton to visit Middle East

The State Department said Clinton will follow her visit to Pakistan with a trip to the Middle East to meet Israeli and Palestinian leaders over the weekend.

Clinton and special Mideast peace envoy George Mitchell will see Israeli Prime Minister Benjamin Netanyahu and Palestinian President Mahmoud Abbas in separate meetings at locations and times yet to be determined, the department said Thursday.

Clinton told U.S. President Barack Obama last week that Mitchell had made little progress.

State Department spokesman P.J. Crowley noted that "challenges remain as we continue to work with both sides.

"Her visit reflects the administration's commitment — and her personal commitment — to work through the challenges we face in pursuit of comprehensive Middle East peace," Crowley said in a statement.

With files from The Associated Press