In an interview with The New York Times published in its Tuesday edition, Aquino said the Philippines is facing pressure from a strong power pushing it to abandon part of its sovereignty.
Drawing a comparison to Hitler's invasions during World War Two, Aquino called for nations around the world to do more to help hold back China's maritime expansion.
The interview came as the Philippines remains at odds with China over the territorial rights to groups of islands and nearby waters in the South China Sea.
China claims jurisdiction over almost all of the South China Sea. It put shoals within the Philippines' exclusive economic zone under its control 2 years ago.
Last year, the Philippines filed a legal complaint with an international tribunal against China's territorial claims in the waters.