SHANKSVILLE, Pennsylvania, (AFP) - Republican White House hopeful John McCain commemorated September 11 attacks from the crash site of United Airlines Flight 93 in rural Pennsylvania, commending "the courage and sacrifice" of its passengers. They "grasped the gravity of the moment, understood the threat, and decided to fight back at the cost of their lives" said McCain about passengers aboard the fourth airplane that went down seven years ago. McCain said the actions of the passengers might have saved his own life, as some believe the terrorists wanted to fly the plane into the US Capitol. Joined by his wife, Cindy, the senator from Arizona welcomed families of victims at the temporary memorial, which amounts to a bronze plaque, two flag polls and a large wooden cross on a exposed windy hilltop above the crash site. In Moscow, Russian President Dmitry Medvedev asked the United States to join Russia in combating terrorism rather than propping up "rotten regimes," . "Russia is ready for coordinated, fully-fledged cooperation on the issue of combating terrorism, with the United States and other countries,"  Medvedev said on the seventh anniversary of the Sept 11 attacks on the United States. "This is a priority and we consider it much more useful for the United States than developing relations with rotten regimes that embark on military adventures," he said, alluding to tensions with Washington over Georgia. He added, "This is a sorrowful day for the United States and all other countries that suffer from terrorism. Humanity has still not overcome this challenge." In Kabul, Afghan President Hamid Karzai Thursday called for a complete end to civilian casualties in the anti-extremism fight after a US strike last month which Afghan and US officials say left 90 villagers dead. As thousands of US troops stationed here fell silent to mark 9/11, the latest deadly Taliban car bomb killed two bystanders in Kandahar and another blast in Ghazni wounded seven. Britain announced that one of its soldiers died in a bomb an attack on Wednesday while the US-led coalition said it had killed "several militants," although locals said three civilians were among the dead. The US says the area is a safe haven for insurgents who are a threat to Afghanistan and the world. Karzai paid tribute to the international soldiers in his country to help tackle insurgent violence and expand the Afghan security forces, destroyed in a civil war that preceded the Taliban's 1996-2001 government. He also said there had been mistakes, notably the number of civilians being killed in military operations. "We want civilian casualties in Afghanistan not only to reduce but to stop totally," Karzai said. The country's campaign against extremist militants would only succeed if it had public support, he said, referring to disaffection caused by the killing of ordinary Afghans. US military bases in Kabul and at Bagram, north of the capital, meanwhile held ceremonies to remember the 3,000 people killed on September 11, 2001 with one featuring members of the New York National Guard who were among the first to respond. "War remains a brutal endeavour and mistakes are made but we remain totally committed to the people of Afghanistan," the most senior US commander in the country, General David McKiernon, told soldiers at the largest US base at Bagram. "We will win this war for our countrymen, for the Afghan people and for the world," he said. Meanwhile, British Prime Minister Gordon Brown said Thursday that the world must increase its pressure on the "frontline" against Al-Qaeda in Afghanistan, seven years after the Sept 11, 2001, attacks. Paying tribute to the victims of the attacks, he welcomed pledges of more troops to fight Taliban militants in the still strife-torn country, from where Al-Qaeda leader Osama bin Laden planned the strikes on US buildings with hijacked airliners. Likewise, the French Foreign Ministry said that the fight against terrorism must address the root causes of extremism, and not only target terror networks. Seven years to the day after hijackers slammed airliners into WTC and the Pentagon in Washington, France, which holds the EU presidency, said the fight against terrorism must be "waged unflinchingly".