Gen. David Petraeus, newly in charge of America's two wars, arrived in Pakistan Sunday as part of his first international trip as head of the U.S. Central Command.
Petraeus' trip signals Pakistan's crucial role in the fight against terrorism, particularly the escalating war in neighboring Afghanistan.
But it also comes amid tensions over suspected American missile strikes in Pakistan — a U.S. ally threatened with financial ruin, torn by an Islamic insurgency and armed with nuclear weapons.
Petraeus, who took the new position on Friday after 20 months as the top U.S. commander in Baghdad, was accompanied by U.S. Assistant Secretary of State Richard Boucher, the U.S. Embassy confirmed late Sunday.
Acting embassy spokesman Wes Robertson declined to provide specifics of the schedule for the two Americans but said they would meet with government and military officials.
In Pakistan's northwest border region, a suicide bomber detonated his vehicle at a checkpoint on Sunday, killing eight troops just hours before Petraeus' arrival.
The attacker rammed his vehicle at a checkpoint near the main gate of the Zalai Fort as Frontier Corps troops gathered nearby, said Maj. Gen. Athar Abbas, the Pakistan army's top spokesman. Eight people died and four were wounded, he said.
The fort is 12 miles outside Wana, the main town in South Waziristan, a tribal region considered a hub for al-Qaida and Taliban fighters involved in attacks on U.S. and NATO troops in Afghanistan.
South Waziristan was the site of one of two suspected U.S. missile attacks on Friday that killed 29 people, including several suspected foreign militants, intelligence officials said.
It was not immediately clear if Sunday's suicide attack was linked to the missile strikes, which have strained Pakistan's alliance with the United States and spurred militant calls for revenge. Pakistani troops have been frequent targets of escalating attacks by militants who want the country to end its support of the U.S.
Under American pressure, Pakistan has deployed security forces throughout its northwest in an attempt to tamp down growing militancy.
Washington is suspected in at least 17 missile strikes in northwestern Pakistan since August, a potential indication that the U.S. is not satisfied with Pakistan's efforts.
Pakistan routinely protests the missile attacks as violations of its sovereignty, but the strikes have continued nonetheless.