CHICAGO, United States: Neil Armstrong, the first man on the moon, will be buried at sea, a family spokesman said Thursday.

"I suspect it will be a private service," spokesman Rick Miller told AFP.

He said further details were not immediately available.

The burial will take place after a September 13 public memorial in the US capital.

NASA chief Charles Bolden, present and former astronauts and other dignitaries are expected to attend the ceremony at the Washington National Cathedral in honor of Armstrong, who died on August 25 at the age of 82.

Armstrong, who died of complications from cardiovascular surgery, grew up in rural Ohio and flew in the US Navy before joining the US space program.

The Apollo 11 commander strode into the history books on July 20, 1969, when he became the first person to walk on the moon, famously calling it "one small step for (a) man, one giant leap for mankind."

The Washington cathedral includes the famous stained glass Space Window, housing a moon rock brought back by Armstrong and fellow astronaut Buzz Aldrin from their Apollo 11 mission.

Next week's service is scheduled to begin at 10:00 am (1400 GMT).

Flags flew at half staff across the United States last week as family, friends and fellow astronauts gathered in Ohio to remember Armstrong at a private service.