(Adds details on SPR fill, link to factbox)
BEIJING, Nov 20 (Reuters) - China made its first official announcement about the country's strategic petroleum reserve (SPR) on Thursday, saying the first phase of the government emergency stockpile is storing about 91 million barrels of crude oil, or about nine days of oil use.
The announcement by the National Bureau of Statistics (NBS) came after President Xi Jinping made a pledge during the G20 summit over the weekend to start regularly releasing information on the country's oil inventories.
The report by the statistics bureau gave details of the four sites that make up the SPR's first phase, but did not mention the larger second or third phases, some details of which have been released through official media and government think-tanks.
China, the world's second-largest oil consumer, imports nearly 60 percent of the crude it consumes, and eventually aims to meet the OPEC standard of stockpiling enough to cover 90 days of net imports.
It has been reluctant to share oil stocks data, arguing that it would be put at a disadvantage in making oil purchases if the data were public.
The SPR's first phase, located in four coastal sites, was fully filled by early 2009 as China took advantage of a steep falls in the global oil markets amid the financial crisis, Zhang Guobao, the top energy official at the time said.
The statistics bureau said on Thursday the oil bases are storing a total of 12.43 million tonnes of crude, or 91 million barrels, just under 90 percent of the total storage capacity of 103 million barrels.
It was not clear if the oil in these tanks has been swapped for new stocks in the five years since it was first filled.
China said on Wednesday that it planned to complete the construction of the second phase by 2020, partly by encouraging private investment in the storage facilities.
Industry officials and traders believe the second phase, designed to hold 170 million barrels, is partially filled. The government has said it plans to begin the third phase by 2020.
Under the first phase, the Zhoushan site is storing 3.98 million tonnes of crude, the Zhenhai site is holding 3.78 million tonnes, Dalian has 2.17 million tonnes and Huangdao 2.5 million tonnes, the statistics bureau said.
In his pledge, Xi did not say how often China would release inventory data. (Reporting by Niu Shuping, Chen Aizhu and Adam Rose; Editing by Richard Pullin)