A bomb attack Wednesday in Afghanistan's volatile southern city of Kandahar killed the director of the local office responsible for arranging pilgrimages to Islamic holy sites, police said.

One other person was killed in the attack on Mohammad Hassan Taimuri and two people were wounded, Kandahar police chief Sher Mohammed Zazai said.

The bomb appeared to be a remote-controlled device concealed on a motorcycle which exploded Wednesday morning just as the director was leaving his office, according to witness Asad Jan Aghra. The Interior Ministry, which oversees Afghanistan's police force, said an investigation was under way.

There was no immediate claim of responsibility, and it was not clear why anyone would target the director, whose job makes him responsible for managing Islamic religious institutions and arranging pilgrimages to the Islamic holy cities of Mecca and Medina. The pilgrimages are called the hajj, which Muslims are obligated to make at least once in a lifetime.

However, Taliban insurgents who are highly active in Kandahar routinely target government figures and institutions. The city is a longtime stronghold of their hard-line Islamist movement and the focus of the American-led operation against the insurgents.

Assassinations of serving and retired government officials — including police — have become virtually a daily occurrence in the city in recent weeks, according to residents who blame the local authorities for failing to secure the area. In the general atmosphere of lawlessness, not all violence is blamed on the Taliban.

"Kandahar city has become an open place for thieves and insurgents. The government is failing and putting their failure on the shoulders of the Taliban," taxi driver Niyamat Agha said.

The attacks on civilians come amid a particularly bloody stretch for the international coalition in Afghanistan, with 19 U.S. service members killed in only four days — most in the south.

NATO on Wednesday said coalition and Afghan forces were pursuing a Taliban commander in charge of some 40 fighters who was linked to a roadside bomb attack Tuesday in the eastern province of Logar that killed four U.S. soldiers.

The U.S. death toll for August stood at 56 — three-quarters of them in the second half of the month as the Taliban fought back against U.S. pressure. American losses accounted for more than 70 percent of the 76 fatalities suffered by the entire NATO-led force.

Until the late month spike, it appeared that the death toll for August would be well below the back-to-back monthly records of 66 in July and 60 in June.

The reason behind the sudden spike in deaths was unclear because few details about the casualties are released for security reasons.

NATO Secretary-General Anders Fogh Rasmussen on Tuesday told reporters in Copenhagen, Denmark, that higher casualties were inevitable because more troops have arrived in Afghanistan in recent weeks, bringing the overall alliance force to more than 140,000 — including almost 100,000 Americans. The U.S. figure is more than triple the number of American service members in Afghanistan at the beginning of last year.

When complete, the surge in U.S. troops will be larger than the 30,000 initially approved because U.S. Defense Secretary Robert Gates has authorized an additional 1,300 specialized forces on top of that, U.S. defense officials say.

Under current projections, U.S. forces will top out at just under 100,000 later this fall, including 31,200 surge troops. The United States plans to begin withdrawing at least some forces next July.

On Tuesday, visiting British Deputy Prime Minister Nick Clegg told British troops in Helmand that the military campaign in Afghanistan was "turning the corner."

"We hear so much bad news," he told the soldiers. "Of course the country mourns when people lose their lives. People are full of anguish when there are serious injuries. But what I have seen today is a complete transformation of the military effort that I first saw when I visited two years ago."

In its monthly summary of Afghan operations, NATO said more than 500 insurgents had been detained in August and 160 killed, including 53 Taliban leaders and 23 commanders working with the allied Haqqani network. Leaders killed included shadow governors seeking to enforce the Taliban's harsh version of Islamic justice in areas where the insurgency holds sway, along with field battle commanders and their lieutenants.

"The insurgent groups are feeling the increased pressure. August was an extremely successful month for Afghan and coalition forces in which several high-level Haqqani and Taliban leaders were captured," said Col. Rafael Torres, a NATO spokesman.