Thousands of activists from an alliance of religious parties streamed toward Islamabad in a massive convoy of vehicles Sunday to protest the government's decision to reopen supply line for U.S. and NATO troops fighting in Afghanistan. The demonstration, which started in the eastern city of Lahore, was organized by the Difah-e-Pakistan Council, or Defense of Pakistan, a group of politicians and religious leaders who have been the most vocal opponents of the supply line. The protest started Sunday in the center of Lahore, where several thousand people assembled with scores of buses, cars and motorbikes. They linked up with thousands more supporters waiting on the city's edge and drove toward Islamabad in a "long march" against the supply line. The convoy included about 200 vehicles carrying some 8,000 people when it left Lahore, said police official Babar Bakht. Once they complete the four hour journey to Islamabad, they plan to hold a protest in front of the parliament building. "By coming out on the streets, the Pakistani nation has shown its hatred for America," one of the Difah-e-Pakistan leaders, Maulana Samiul Haq, said in a speech on the outskirts of Lahore. Supporters showered him with rose petals as he rode through Lahore in the back of a truck with other Difah-e-Pakistan leaders, including Hafiz Saeed, chief of Jamaat-ud-Dawa; Hamid Gul, a retired Pakistani intelligence chief with a long history of militant support; and Syed Munawar Hasan, leader of Pakistan's most powerful Islamist party, Jamaat-e-Islami. Many demonstrators rode on the tops of buses, waving party flags and shouting slogans against the U.S. and NATO . "One solution for America, jihad, jihad!" they shouted. The crowd was dominated by members of Jamaat-ud-Dawa. "The movement that has been started to reverse the government's decision to restore the NATO supply will go on until America leaves this region for good," Saeed said in a speech on the outskirts of Lahore. "The mission is noble because it is to save the country and the nation from slavery." Difah-e-Pakistan leaders have vowed to stop NATO trucks from making the journey from Karachi to the Afghan border. Although the army was outraged by the U.S. attack on its troops, which Washington said was an accident, it was eager to repair the relationship to free up more than $1 billion in military aid that had been frozen for the past year. The U.S. waited so long to apologize in part because the Obama administration was apparently worried such a move would expose it to criticism from Republicans in a presidential election year.