Anger over the burning of the Muslim holy book erupted into deadly violence for the second straight day Saturday in Afghanistan, with demonstrators setting cars and shops ablaze in a riot that left at least five civilians dead, officials said.

The desecration of the Koran at a small Florida church has outraged millions of Muslims and others worldwide, fueling anti-American sentiment that only further strains ties between the Afghan government and the West.

Underscoring the tensions, two suicide attackers disguised as women blew themselves up and a third was gunned down when they attacked NATO base on the outskirts of Kabul.

The Koran was burned on March 20, but many Afghans only found out about it when Afghan President Hamid Karzai condemned the desecration four days later. Protests broke out on Friday in Kabul, Herat in western Afghanistan and thousands flooded the streets of Mazar-i-Sharif, the provincial capital of Balkh province in the north.

Hundreds of Afghans, carrying long sticks and holding copies of the Koran over their heads, also marched through Kandahar, the largest city in southern Afghanistan and the cradle of the insurgency. The crackle of gunfire could be heard throughout the city, which was blanketed by thick black smoke.

Security forces shot in the air to disperse the crowd, said Zalmai Ayubi, a spokesman for the provincial governor. It's unclear how the five protesters were slain, he said.

Daud Ahsam, a doctor in the emergency room at Kandahar's Mirwais Hospital gave the death toll and said 53 people also were hurt. Shops and restaurants throughout the city were shuttered and routes leading into the city were blocked by security forces.

An Associated Press photographer estimated the crowd at a few thousand and said demonstrators had smashed his camera and roughed up other journalists.

The bloodshed came a day after Afghans protesting the Koran burning stormed a U.N. compound in the northern city of Mazar-i-Sharif, leaving four Afghan protesters and seven foreign U.N. employees dead, including four Nepalese guards. The other three were identified by officials in their home countries as: Joakim Dungel, a 33-year-old Swede; Lt. Col. Siri Skare, a 53-year-old female pilot from Norway; and Filaret Motco, a 43-year-old Romanian who worked in the political section of the U.N.

Karzai's office said the president spoke on the telephone Saturday morning with U.N. Secretary-General Ban Ki-moon. Karzai asked the secretary-general to extend his condolences to the families of the slain U.N. workers. He also called on the U.N. to help promote religious tolerance throughout the world to ease friction between people of different faiths. Karzai said Afghan officials were investigating the U.N. attack and would bring the perpetrators to justice.

In Florida, Wayne Sapp, a pastor at the church, called the events "tragic," but said he did not regret the actions of his church.

"I in no way feel like our church is responsible for what happened," Sapp said in a telephone interview on Friday.

Afghan authorities suspect insurgents melded into the mob outside the U.N. compound and they announced the arrest of more than 20 people, including a militant they suspect was the ringleader of the assault. The suspect was an insurgent from Kapisa province, a hotbed of militancy about 250 miles (400 kilometers) southeast of the city, said Rawof Taj, deputy provincial police chief.

Taliban spokesman Zabiullah Mujahid sent a text message to The Associated Press on Saturday denying that the insurgency was responsible for killing the U.N. workers.

Demonstrators have alleged that the four protesters were killed by Afghan security forces. Interior Ministry spokesman Zemeri Bashary said Saturday that a delegation of high-ranking Afghan officials was being sent to the city to investigate the what happened during the demonstration in which seven vehicles, including a police vehicle, were burned.

"When the demonstration started, the number of people increased every minute to around 5,000," Bashary said. "The police did take action, but we are investigating how these casualties occurred. Were the steps and actions by police adequate or not?"

Bashary also gave reporters details of Saturday's attack on Camp Phoenix, a base on the east side of Kabul that's used to train Afghan security forces.

He said three armed insurgents wearing suicide vests arrived at a main gate at the base around 6:45 a.m. Two of the attackers opened fire and then detonated their vests of explosives, Bashary said. The third opened fire and was killed by NATO forces. The body of a fourth person, an Afghan man at the scene, has not been identified. Three NATO service members were injured.

The gate at the base was scorched from the explosions. An AP reporter at the scene saw the remains of at least one of the attackers dangling from the gate. Police officer Mohammad Shakir told the AP that two suicide bombers were clad in blue burqas, the all-encompassing coverings worn by many women in Afghanistan.

Also Saturday, NATO confirmed that coalition and Afghan security forces killed an insurgent who operated a suicide attack network in Iman Sahib district of Kunduz province in northern Afghanistan, which has seen an uptick in violence.

The coalition said the insurgent, who was killed Friday after fleeing to a ditch, orchestrated the Feb 21 suicide attack on a government office in the district, killing 29 civilians and an Afghan police officer. He also had a role in the March 10 suicide attacks in Kunduz province against Afghan security forces that killed at least 35 Afghans, including the provincial police chief, NATO said.


Associated Press writer Deb Riechmann in Kabul and Mirwais Khan based in Kandahar contributed to this report.