Chinese research vessels were "loitering" in the area of Philippine (Benham) Rise within the Philippine exclusive economic zone.

In his X (formerly Twitter) account, Raymond Powell, Sealight Director at Stanford University's Gordian Knot Center for National Security Innovation said two Chinese research vessels were spotted loitering in the area on Friday.

The two Chinese vessels were identified as Haiyang Dizhi Liuhao and Haiyang Dizhi Shihao.

Powell said the two vessels left the port at Longxue Island in Guangzhou, China on February 26 and moved east southeast through the Luzon Strait.

"As of 1 March they are loitering east of Luzon in the Northeast corner of Philippine (Benham) Rise, which is in the Philippines' exclusive economic zone," he said.

The Benham Rise, which was renamed Philippine Rise in 2017, is approximately 24 million-hectare undersea region on the east of Luzon.

According to the National Museum, the Philippine Rise "includes a 13.4 million-hectare outer section that was validated by the United Nations Commission on the Limits of the Continental Shelf as part of the Philippine territory in 2012. It is about 3,000 to 3,500 meters deep covering the vast coasts off as far as Cagayan to Catanduanes provinces."

"In May 2018, the 352,390 hectares, a portion of the Philippine Rise was proclaimed as Philippine Rise Marine Resource Reserve and 49,684 hectares was declared as a Strict Protection Zone within the reserve or area for actual ground survey and delineation for only Filipino scientists and the remaining areas within the PRMRR are collectively designated as Special Fisheries Management Area," it stated. Robina Asido/DMS