Activists chant slogans as they display placards during a rally regarding the disputed islands in the South China Sea, in Manila, Nov. 12, 2015. Reuters

China has taken possession of more of the South China Sea, stationing ships in waters used by Philippine fishermen, the Philippine Star reported, citing unidentified people. China has sent five ships to the area — known as Jackson or Quirino atoll — which are barring fishermen from entering, the report said.

The ships have been in the area for about a month, the Star reported, citing Eugenio Bito-onon, mayor of the nearby Kalayaan island group. Fishermen said they were "chased away," according to the report.

The Philippines is still verifying the report with "concerned agencies," foreign affairs spokesman Charles Jose said in a text message to International Business Times. There are Chinese ships in the general area but it is not clear if their presence is "permanent," Reuters quoted Philippine military spokesman General Restituto Padilla as saying.

The Chinese embassy in Manila didn't immediately reply to a query.

The atoll — coral reefs that form a lagoon within a larger body of water — is close to Philippine-occupied Lawak island and Mischief Reef, which China has occupied since the 1990s under Philippine protest.

China, which claims most of the South China Sea, has stepped up its occupation in the past two years by expanding or building islands via reclamation projects. Besides the Philippines, Vietnam, Malaysia, Brunei and Taiwan also claim parts of the sea, where about half of global shipping passes through, and which are estimated to hold vast gas deposits. Last month, Vietnam protested China's alleged installation of missiles in the Paracel Islands, just days after calling for more U.S. involvement in the South China Sea.

U.S. President Barack Obama has called on China to stop reclamation projects and the U.S. has pledged to continue to send warships into the sea — including waters claimed by China — in so-called freedom of navigation operations, or FONOPs.

The Philippines has taken its case against previous perceived encroachments to an international tribunal in the Netherlands, which is expected to rule by May, though China has refused to participate or recognize its jurisdiction. The Philippines received old U.S. ships to beef up its small navy and this week signed an agreement to receive military equipment from Japan.