British military authorities said five British troops died in two explosions in southern Afghanistan on Friday, Reuters reported.
The five, from the 2nd Battalion The Rifles, died when the blasts hit them while on a foot patrol near Sangin in Helmand Province, the Ministry of Defence said.
It was the worst loss from a single attack since Britain joined the U.S.-led invasion of Afghanistan in 2001.
The latest fatalities mean 184 British soldiers have now died in the Afghan conflict, passing the 179 who died during the war in Iraq.
Three other deaths were announced earlier on Friday.