LONDON , England ( CNN ) -- Central London fell silent save for the tolling of Big Ben as the United Kingdom honored the dead of wars past and present on Remembrance Sunday . Queen Elizabeth II then laid a wreath at the Cenotaph , the war memorial on Whitehall near Parliament , after a military band played the `` Last Post . '' Other members of the royal family , including her husband , Prince Philip , and grandchildren Princes Harry and William , followed suit under steel-gray skies as Britain marked a tradition going back to the end of World War I. Harry was representing his father Prince Charles , the heir to the throne , who is in Canada . Hours before the ceremony began , the Ministry of Defence announced the 200th British soldier had been killed in hostile action in Afghanistan . The soldier , from the 2nd Battalion , The Rifles , was killed in an explosion in Helmand province , the main British area of operations , in southern Afghanistan . That was then followed by the news that another soldier from 4th Battalion , The Rifles , died from injuries sustained in an explosion that happened in the same region near Sangin . Both soldier 's families have been informed , the Ministry of Defence said . An American soldier was also killed in an insurgent attack in western Afghanistan , the International Security Assistance Force said in a statement . The event was not related to an ongoing search for two U.S. Army paratroopers , who went missing Wednesday near Afghanistan 's border with Turkmenistan , ISAF said . The service member 's name was not released . British troops also marked Remembrance Sunday in Afghanistan . The country honors war dead each year on the Sunday closest to November 11 , the day World War I ended in 1918 . The memorials this year come as many Britons question the country 's military mission in Afghanistan . The UK has about 9,000 troops there , the second-largest contingent after the United States . Prime Minister Gordon Brown attempted to shore up support for the eight-year-old mission Friday . `` Our mission must not fail , '' Brown said . `` It is not easy , the choices are not simple , there is no strategy that is without danger and risk , but that is the responsibility of leadership of government and of our armed forces -- to do what is necessary , however difficult , to keep the British people safe . `` We can not , must not , and will not walk away , '' Brown said . Sunday marked the first Remembrance Sunday since the death of the last two British World War I veterans living in the U.K. , Harry Patch and Henry Allingham . Patch , 111 , and Allingham , 113 , died within a week of each other in July . Brown and other political leaders laid wreaths after the royal family at the Cenotaph , a memorial designed by the eminent early 20th-century architect Edward Lutyens . Diplomats from countries that used to be part of the British Empire followed , as did uniformed and civilian leaders of the British military . Rows of uniformed veterans stood on Whitehall for the service , wearing red paper poppies in their lapels . The Royal British Legion sells the paper poppies every year to raise money for veterans ' causes . They are ubiquitous across the country in the weeks leading up to Remembrance Sunday . The ceremony lasted about 20 minutes from the moment of silence at 11 a.m. ( 6 a.m . ET ) through the singing of `` God Save the Queen '' after a short service led by the Bishop of London , Richard Chartres . After the royal family left the memorial , military veterans and members of the public also walked past the Cenotaph .
Queen Elizabeth II and Royal family lay wreaths at the Cenotaph , the war memorial near Westminster in London . Britain honors its war dead each year on the Sunday closest to November 1 , the day World War I ended in 1918 . Hours before the ceremony began , the 200th British soldier was been killed in hostile action in Afghanistan . That was followed by the announcement that a U.S. soldier and another British soldier died in separate incidents .