KABUL (Reuters) - Afghanistan's government says a new investigation shows 39 civilians, all women or children, were killed in a NATO rocket attack last month, fewer than first reported but dozens more than foreign forces have conceded.

The NATO-led International Security Assistance Force (ISAF) said it has been checking reports of civilian deaths since the government first said nearly two weeks ago that over 50 people had been killed by a rocket strike in southern Helmand province.

On Thursday, an ISAF spokesman, Lt. Raymond Jeffery, said he had no information about the result or progress of any probe and could not comment on the 39 deaths reported by President Hamid Karzai's office late on Wednesday.

ISAF previously said an initial assessment showed six people died in an incident in the area and at the time in question, and that a "majority" were insurgents.

Those killed in the rocket were civilians who had crammed in a house after fleeing a clash between the Taliban and joint Afghan and foreign forces, the Afghan presidential office said in its statement.