Petley Reef

Petley Reef ; Núi Thị Reef ; Mandarin, is a reef on the northern part of the Tizard Bank of the Spratly Islands in the South China Sea. The reef has been occupied by Vietnam since 1988. It is also claimed by China, the Philippines, and Taiwan.
The Vietnamese Navy is stationed on a complex of structures called Thị Island, with geographical coordinates recorded on the sovereignty marker as 10°24′40″N 114°34′48″E. This military outpost is connected by a bridge to a multi-purpose cultural center completed in December 2018.
Starting in June 2025, Vietnam began land reclamation activities at Núi Thị Reef.