UPDATE 1-US safety board says will issue report on Boeing 787 probe Thursday

WASHINGTON, March 6 (Reuters) - The U.S. National Transportation Safety Board will issue an "interim factual report" at 11 a.m. ET Thursday on its investigation into a battery fire aboard a Japan Airlines Boeing 787 Dreamliner plane on Jan. 7.

The information will be "factual in nature and does not provide any analysis," the agency said.

Sources familiar with the matter said the report would not include conclusions about the cause of the fire, or recommendations for the Federal Aviation Administration, which is considering a proposal by Boeing Co to address the risks of fire aboard the plane. FAA approval of the plan could come within days, according to sources familiar with the plan.

The report marks a milestone in the agency's probe into one of two lithium-ion batteries that burned on 787 jets in January. Japanese regulators are investing the second incident.

However, the NTSB is still early in the investigation into the cause of the blaze. Because the battery was badly burned in the Jan. 7 fire in Boston, investigators may never determine a root cause, experts said.

Boeing delivered its plan to address the battery risks to the FAA on Feb. 22.

"The FAA has indicated they are evaluating our proposal for a permanent fix to address the 787 battery issue and we are encouraged by the progress being made toward resolving the issue and returning the 787 to flight," Boeing spokesman Marc Birtel said.