Kandahar, Afghanistan ? Suspected Taliban militants used rocket-propelled grenades to ambush a British patrol on Tuesday, killing three soldiers just one day after NATO took command of southern Afghanistan.

The attack in Helmand province seriously wounded a fourth soldier and marked the deadliest single incident suffered by British forces since they deployed here in late 2001 to help topple the Taliban regime for harboring Osama bin Laden.

The attack followed NATO’s assumption of control Monday of military operations in southern Afghanistan from the U.S.-led coalition. It also underscored the dangers faced by the 8,000-member multinational contingent to try and crush the bloodiest spate of Taliban-led violence in nearly five years.

Afghan officials reported that heavy fighting in Helmand’s Musa Qala district started early Tuesday. One vehicle, apparently carrying the soldiers who were killed, was destroyed and another damaged in the ambush. Harrier fighter jets and Apache attack helicopters strafed Taliban positions and “inflicted some casualties,” said Brig. Ed Butler, the British force commander. A NATO statement said at least one insurgent was killed.