A British soldier was killed in action Sunday in the restive southern Afghan province of Helmand, the Ministry of Defence said.

"It is with regret that we can confirm that a member of the UK Armed Forces has been killed in action this afternoon during ongoing operations against insurgent positions in Helmand Province, Southern Afghanistan," the ministry said in a statement.

The ministry said no further details were available and the deceased's next of kin were being informed.

The International Security Assistance Force said in a statement from Kabul that a soldier serving with NATO had been killed during an attack in Helmand.

It was the ninth soldier to be killed in southern Afghanistan since NATO took command of military operations there last Monday.

The chief of the British Army had earlier defended the military operation in Afghanistan after it was reported Sunday that soldiers there were being stretched to "the brink of exhaustion" by Taliban fighters.