Kabul, Afghanistan (CNN) -- A suicide bomber attacked police headquarters in the volatile city of Kandahar on Friday, killing a top police official and two others, the Interior Ministry said.
Khan Mohammad Mujahed -- the police chief of Kandahar province, in the country's war-wracked southern region -- was slain, Interior Ministry spokesman Zemary Bashary said.
Mujahed had been leaving the office for home when a man wearing a military uniform detonated a bomb at the entrance of police headquarters. Along with the police official, the director of the Kandahar terrorism department and another police officer died.
"Three other policemen were seriously injured," Bashary said.
The violence erupted after U.S. Secretary of State Hillary Clinton said in prepared remarks at a NATO conference of foreign minister in Berlin that "we should recognize that we are on the cusp of what promises to be a violent spring fighting season."
"We have to steel ourselves and our publics for the possibility that the Taliban will resort to the most destructive and sensational attacks we have seen," she said.
Kandahar, which has a strong militant presence, is the birthplace of the Taliban and has been the scene of fierce fighting over the years between international forces and insurgents.
It has been wracked with anti-American demonstrations lately over the burning of a Quran, the Muslim holy book, in the United States.
In this, as in other instances, the International Security Assistance Force condemned the strike and vowed to find the attackers.
"Our prayers are with the families and friends of those suffering from today's terrible losses," said Gen. David Petraeus, commander of ISAF.
"This attack was the act of cowardly insurgents desperate to prevent the empowerment of the Afghan Security Forces and the Afghan people."
The U.S. Embassy in Kabul called the attack "deliberate and brutal attack" and said it displayed the "cowardice and inhumanity of terrorists."
"Police Chief Mujahed was a highly respected senior member of the Afghan National Police Force who dedicated his career to maintaining security and stability for his country. We commend the brave law enforcement personnel who risk their lives to protect the people of Kandahar, and we know that the loss of Police Chief Mujahed will be strongly felt," the Embassy said.
The Quran burning by a U.S. pastor swept through Kandahar, where there have been a series of demonstrations, including one April 3 that left three dead and another April 2 that resulted in nine deaths and more than 70 injuries.
The first big protest against the Quran burning occurred in the northern Afghan city of Mazar-e Sharif, when demonstrators stormed a United Nations office and killed 12 people.
The demonstrations were sparked by the actions of controversial Florida pastor Terry Jones, who presided over what he called a trial of the Quran on March 20. The holy book of Islam was "found guilty" by members of Jones' tiny church and burned, according to a release posted on the church's website.
There have been other recent strikes targeting security forces.
In February, two mines went off in a playground, killing 10 people, at a picnic hosted by the former police chief of Arghandab district in the province.
In the same month, at least 19 people were killed and 49 wounded when armed attackers targeted a police headquarters in Kandahar. The attack killed 15 police officers, one Afghan soldier, a government security officer and two civilians.
Canadian and U.S. forces are stationed in Kandahar province. Clinton cited an effort to help civilians bolster their "governance, civil society and economic development" in places like Kandahar city and Marja, in nearby Helmand province.
"We all know there will be tough moments ahead," Clinton said.
"The Quran burning and the violence that followed was one of those moments. We deeply regret that hateful gesture and deplore the inexcusable attacks that followed on the U.N.'s compound in Mazar-e Sharif and innocent Afghan civilians."
Journalist Reshad Fazel contributed to this report.