Afghanistan Tries to Block Video and Head Off Rioting KABUL, Afghanistan - Racing to head off potentially violent demonstrations over an anti-Islamic video, the Afghan government on Thursday pushed Internet providers to shut down access to Web sites hosting the clip, and asked political and religious leaders to urge calm, senior Afghan officials said. The quick action stood in contrast to a slow government response in February after deadly rioting broke out at the news that American soldiers had burned Korans. In that case, Afghan officials were slow to try to head off violence, and American officials later said they were concerned and angered by the delay. At least 29 Afghans and six American service members were killed by members of the Afghan security forces in days of violence after the Koran burning. The decision Thursday to ask Internet companies to block access to YouTube and related Google-owned Web sites through which people could have gained access to the video was a first for the country, where the Internet is still a rarity outside the capital. By early evening, YouTube, Google News and Gmail could not be reached in the capital, and Google's browser, Google Chrome, was also blocked. The blockage was not uniform and the sites were still accessible on some smartphone devices, but only a small percentage of Afghans own those. The Afghan government also sent an official letter of complaint to YouTube for providing access to a video that insulted and abused Islam's founder and asked that the company remove it from the Web site. In a statement, Google, which owns YouTube, said that the video would not be taken down, but that the company was working with the governments of Libya and Egypt, at their request, to block access to it in those countries. It was unclear late Thursday whether that cooperation was occurring in Afghanistan as well. President Hamid Karzai condemned the video as soon as news of it spread on Wednesday afternoon, and repeated that condemnation Thursday in a sober statement that described his conversation late Wednesday with President Obama in which it said the two leaders "denounced the film and termed it as insulting to Islamic beliefs and values." While Mr. Karzai did not personally call for calm in his statement, he and his government turned to influential people in communities across the country to tamp down emotions and urged clerics to avoid provocation at the weekly Friday Prayer. In the past, it has often been radical religious leaders here who have incensed the faithful to violence. In March 2011, it was clerics who inflamed their congregations over a Florida pastor's burning of the Koran, contributing to angry men pouring into the streets of the northern city of Mazar-e-Sharif and killing seven international United Nations staff members in a United Nations guesthouse. "We must keep people quiet about this," said Rangin Spanta, the national security adviser, describing Mr. Karzai's behind-the-scenes call for calm. We instructed all security forces of Afghanistan, all governors, all decision makers to work with the elders, to work with the clergy, to work with the imams to not talk, to not provoke people. The NATO-led international military command in Afghanistan immediately issued instructions to Western troops across the country to minimize their exposure to places and situations where there could be violence, said Brig. Gen. Roger Noble, the deputy commander for NATO Operations in Afghanistan. The military told troops to "minimize the chance of being at the wrong time or inadvertently being in a place that might inflame a protest in the next few days," he said and underscored that the international forces have "strong" respect for the Afghans" Muslim faith. Although senior Afghan government officials said they understood that the video was the product of a fringe element in the United States, Mr. Spanta said, "We are very, very sad about it." The overwhelming majority of Afghans are deeply pious and conservative Muslims, and the worry is that the film's trailer, which coarsely portrayed the Prophet Muhammad as a womanizer and murderous thug, would bring Afghans into the streets, willing to do violence both to the government's forces, who work closely with the West, and to foreigners, especially Americans, many of whom live in Kabul. In Kandahar, where the governor and local leaders followed Mr. Karzai's orders and held a lengthy closed meeting to discuss the film and the appropriate reaction, there was an overwhelming sense of pain over the video. "This is deeply and extremely unacceptable for all Muslims all over the world, and this actually generates loathing for the Americans," said Mohammed Omar Satti, a tribal elder in Kandahar and a member of the provincial Peace and Reconciliation Commission. Several Kandahar clerics emphasized that people of all religions were appalled by the video and asked the American government to arrest the man who made it. A Kandahar imam, Mullah Azhar, asked people to be tolerant and condemn it, but to refrain from damaging Muslim property. Like many others, he was genuinely puzzled by free speech laws in the United States that allow such work to be made public. I ask the government of America, why did they allow a person to insult a man, Muhammad, when by insulting him they sadden the whole Muslim world and create hatred toward Americans? Taimoor Shah contributed reporting from Kandahar, Afghanistan, and an employee of The New York Times from Kabul.