Violent protests over the burning of a Qur'an by a Florida preacher rocked Afghanistan for a second day. At least 20 people have been killed in the violence, including seven people affiliated with United Nations.

Nine people died during a demonstration in the southern city of Kandahar on Saturday, while another 81 people were injured as protesters lashed out at Americans and other foreigners in the war-torn country.

Investigators claimed that insurgents may have infiltrated the crowd in Kandahar and set off the violence. Seventeen people have been arrested by Afghan National Security Forces.

The protests were held in response to the burning of a Qur'an last month by the Rev. Terry Jones. The Florida preacher made headlines in 2010 when he first announced plans to burn the Muslim holy book, but backed off amid political pressure.

Jones made good on his threat on March 20 though most Afghans did not hear about it until President Hamid Karzai condemned the move four days later.

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

The incidents follow a violent protest on Friday at a UN compound in the northern city of Mazar-i-Sharif that left at least 11 dead, including four Nepalese guards and three other foreigners.

The UN's top envoy in Afghanistan, Staffan de Mistura, said the organization had no plans to evacuate Mazar-i-Sharif, although 11 staff members from there had been redeployed to Kabul.

"This is not an evacuation; it is a temporary redeployment because the office is not functioning. We will be ready to go back as soon as we can establish an office that is secure enough," he told reporters.

Karzai said he regretted that people had been killed in the protests, and demanded again that the United States and the UN bring Jones to justice.

Meanwhile Lawrence Cannon, Canada's foreign affairs minister, assured reporters on Saturday that no Canadians were caught up in the uprising and the Canadian ambassador and Canadian personnel were entirely safe.

"This is a terrible set of circumstances, we are very concerned about the way that this is taking place," Cannon said. "I can assure Canadians that from a security perspective our Canadian forces as well as all the civilian personnel that are in Afghanistan at this time have and are provided security."

The Afghan-Canadian governor of Kandahar condemned the desecration as an "abhorrent move" by "a stupid pastor."

Wayne Sapp, a pastor at the Florida church, said the events in Afghanistan were tragic but that he did not regret the church's decision to burn the Qur'an.

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

With files from Associated Press