Originally posted by the Voice of America. Voice of America content is produced by the Voice of America, a United States federal government-sponsored entity, and is in the public domain. NATO Troops Kill 4 On Bus in Southern Afghanistan VOA News 12 April 2010 Afghan policemen and protesters stand near a bus after it was fired upon by international troops during a anti-American protest in Kandahar, south of Kabul, Afghanistan, Monday, April 12, 2010 Photo: AP Afghan policemen and protesters stand near a bus after it was fired upon by international troops during a anti-American protest in Kandahar, south of Kabul, Afghanistan, Monday, April 12, 2010 NATO says its troops opened fire on a bus in southern Afghanistan Monday, killing at least four people and wounding 18 others. NATO says its patrol fired on a large vehicle after the driver refused warnings to stop in the Zhari district of Kandahar province. Upon inspection, NATO says its forces discovered the vehicle was a passenger bus.  A woman was among those killed. NATO soldiers took some of the wounded to a military hospital. In a statement, the alliance says it deeply regrets the tragic loss of life. A combined NATO and Afghan team arrived in Zhari to investigate the events. Dozens of Afghans took to the streets in Kandahar city to protest the killings. Demonstrators chanted "Death to America" and called for the downfall of Afghan President Hamid Karzai. They also blocked the main road out of the city. President Karzai condemned the killing in a statement, saying shooting a civilian bus violates NATO's commitment to safeguard civilian life. U.S. General Stanley McChrystal, the commander of U.S. and NATO forces in Afghanistan, told Afghan leaders earlier this month that troops under his command are making the strongest efforts possible to avoid civilian casualties, but he acknowledged his forces sometimes make mistakes. Elsewhere in Kandahar Monday, suicide bombers attacked the Afghan intelligence services compound resulting in a deadly gunfight.  Afghan officials say one bomber blew himself up and another was killed by security forces. Some information for this report was provided by AP, AFP. .