KABUL - Gen. David Petraeus, the new chief of the U.S. Central Command, arrived in Afghanistan on Tuesday for a first-hand look at the war in Afghanistan.

With U.S. deaths at an all-time high in Afghanistan and attacks against westerners on the rise, Petraeus travelled from neighbouring Pakistan on his first visit to the region since taking charge of the U.S.-led wars in both Afghanistan and Iraq.

Petraeus will meet with Afghan leaders and top U.S. military officials, including U.S. Gen. David McKiernan, head of the NATO-led force in Afghanistan.

Col. Greg Julian, the chief U.S. military spokesman in Afghanistan, said Petraeus was in the country for an "initial assessment."

Petraeus, who became Centcom chief Oct. 31, has been credited for stemming the violence in Iraq, and many expect Afghanistan will see some of the same tactics, such as co-opting local tribal leaders to resist the Taliban.

His stop in Afghanistan follows a two-day visit to Pakistan, a U.S. ally which is also battling an insurgency in its tribal areas bordering Afghanistan.

Washington says the region is also believed to be home to many of al-Qaida's top leaders, including Osama bin Laden.

The mountainous, remote area is also used by insurgents blamed for rising attacks on NATO and U.S. troops in neighbouring Afghanistan as well as on targets in Pakistan.

The Pakistani government has complained bitterly about U.S. cross-border missile strikes, and on Tuesday Prime Minister Yousuf Raza Gilani warned that the next U.S. president must halt the attacks or risk losing the war against al-Qaida and the Taliban

"No matter who the president of America will be, if he doesn't respect the sovereignty and integrity of Pakistan ... anti-America sentiments and anti-West sentiment will be there," said Gilani in an interview with The Associated Press in his heavily guarded residence atop a hill in the capital, Islamabad.

The prime minister said the U.S. should share intelligence with his country's military to allow Pakistan to go after militants themselves.

"Either they should trust us and they should work with us, otherwise, I think it's a futile exercise," he said.

As Gilani spoke, several thousand Pakistanis demonstrated against the missile strikes in a town in the border region and in the southern Pakistani city of Karachi, burning U.S. flags, witnesses said.

"Stop killing innocent people, stop messing with our country," they chanted in Karachi.

Democratic candidate Barack Obama and his Republican rival, John McCain, have roughly similar positions on Pakistan, though during the campaign differences in emphasis have emerged.

Obama has said if he is elected, he could launch unilateral attacks on high-value terrorist targets in Pakistan as they become exposed and "if Pakistan cannot or will not act" against them.

McCain says such attacks shouldn't be discussed "out loud" but has not said he disagrees with them.

Though the U.S. now has more troops in Afghanistan than ever -- some 32,000 -- McKiernan has requested at least three more brigades to help the U.S. cover violent areas it now can't reach -- areas where the Afghan government now has little presence.

More than 5,200 people -- mostly militants -- have died in insurgency related violence this year alone.

U.S.-led troops on Tuesday killed five insurgents in the southern Helmand province, after the militants ambushed their patrol, the coalition said in a statement.

Meanwhile, a U.S. civilian shot an Afghan civilian in Kandahar province after the Afghan allegedly set another U.S. civilian on fire, the military said. It did not identify the Americans or who they were working for.