Two British soldiers were killed in the southern Afghan province of Helmand, officials confirmed Thursday, dpa reported.
"A British Royal marine and a British (female) soldier died from wounds they received during a patrol in Nahr-e-Saraj district in Helmand," said Hagen Messers, a spokesman for the NATO-led military alliance.
At least 435 British military personnel have been killed in Afghanistan since the war began in 2001, according to officials.
Nahr-e-Saraj is one of the most violent districts in the country. According to coalition figures, Nahr-e-Saraj witnesses 11 per cent of all enemy-initiated attacks across Afghanistan.
Local media reported it could be an "insider attack," implying that Afghan forces turned their weapons on their NATO allies.
Messers said: "We can't deny nor confirm whether this was an insider attack. We are gathering more details surrounding this incident."
Taliban leader Mullah Omar released a statement late Wednesday saying they had increased the number of insider attacks against coalition and Afghan forces, claiming to have killed more than 50 foreign soldiers this year.
He also urged "every brave Afghan in the ranks of the foreign forces and their Afghan hirelings ... to strike" government and NATO forces.
"Increase your efforts to expand the area of infiltration in the ranks of the enemy," Omar said.