In March 1944 the Imperial Japanese Navy Air Service ordered the construction of an airfield near Marpi Point on the northern end of the island of Saipan as part of a general plan to improve defenses in the Marianas. The airfield was planned to handle 24 aircraft, but was still incomplete at the time of the U.S. invasion in June 1944. During the battle work on the runway continued to allow for the planned airlift of Japanese reinforcements to Saipan; however, this plan was abandoned when it became apparent that U.S. naval and airpower made this unfeasible. On 9 July 1944 the 24th Marines secured Marpi Point and the airfield, while the 25th Marines secured the northeast end of the island. Saipan was declared secure at 16:15 on 9 July.