A roadside bomb and a rocket-propelled grenade in southern Afghanistan killed two British soldiers, while gunmen in the east abducted 16 mine-clearing personnel working for the United Nations, officials said Sunday. The attacks that killed the British troops in Helmand province's Gereshk district came as thousands of U.S. Marines pour into the Taliban's southern heartland, in the biggest U.S. military offensive operation in Afghanistan since the toppling of the militants in 2001. It wasn't clear if the British casualties were involved in the Marine operation taking place in the same province. Britain's Ministry of Defense said both attacks took place near Gereshk in Helmand province on Saturday. Earlier the NATO-led force said the two had died in a single incident. It was not immediately clear what caused the discrepancy in the accounts, The Associated Press reported.