12 killed in Afghanistan after protests over reported Quran burning

Kabul, Afghanistan (CNN) -- At least 12 people were killed Friday in an attack on a United Nations building in Afghanistan that followed a demonstration against the reported burning of a Quran in Florida last month, authorities and a U.N. source with knowledge of the events said.

Eight workers for the U.N. and four Afghans were killed, said Abdul Rauof Taj, security director of Bulkh province. At least 24 people were injured, he said.

A U.N .source confirmed the dead included four Nepalese security guards. U.N. workers from Norway, Sweden and Romania were also among the dead, the source said.

The attack followed a demonstration against the reported burning of a Quran this month by Florida pastor Terry Jones, who gained international attention last year with his plans to burn a Quran, the U.N. source with knowledge of events said.

Jones is the pastor of the Dove World Outreach Center in Gainesville, Florida. He canceled plans to burn a Quran last year, on the ninth anniversary of the September 11, 2001 terrorist attacks. Last month, however, with far less attention than he attracted last year, Jones reportedly burned Islam's holy book.

The church says on its website that it planned to put the Quran on trial on March 20, and, "if found guilty of causing murder, rape and terrorism, it will be executed!" Another post on the website says "the Koran was found guilty" during the mock trial and "a copy was burned inside the building."

Jones said the attacks show that "time has come to hold Islam accountable."

"We must hold these countries and people accountable for what they have done as well as for any excuses they may use to promote their terrorist activities," he said.

The attack on Friday happened at the operations center of the U.N. Assistance Mission in Afghanistan in Mazar-e Sharif, said Dan McNorton, a U.N. spokesman.

"The situation is still confusing and we are currently working to ascertain all the facts and take care of all our staff," he said.

Initial indications are that knives and small arms were used in the attack, according to a U.N. spokesman who declined to be named.

Afghanistan President Hamid Karzai called the attacks "an act against Islam and Afghan values," while U.N. Secretary General Ban Ki Moon said the deadly attack "was a cowardly attack that cannot be justified."

NATO Secretary General Anders Fogh Rasmussen said the victims were only trying to help the Afghan people.

"In targeting them, the attackers have demonstrated an appalling disregard for what the U.N. and the entire international community are trying to do for the benefit of all Afghans," he said.

U.S. President Barack Obama also condemned the attack.

"We stress the importance of calm and urge all parties to reject violence and resolve differences through dialogue," he said.

The United Nations' special representative to Afghanistan, Staffan de Mistura, was on his way to Mazar-e Sharif to assess the situation, McNorton said.