The Philippine defense chief says authorities are trying to verify a report that Chinese coast guard ships have left a disputed shoal and that Filipino fishermen have regained access to the rich fishing area that China seized in 2012.

Defense Secretary Delfin Lorenzana said Friday that the Philippine coast guard has reported that Chinese coast guard ships have not been sighted at Scarborough Shoal in the last three days, but he added that the report still has to be validated.

Lorenzana told The Associated Press that a Philippine air force plane may conduct aerial surveillance of the area off the northwestern Philippines as early as Saturday.

Chinese coast guard ships have been driving Filipino fishermen away from the area since taking control of Scarborough.