President Ferdinand Marcos Jr. said on Monday the presence of a Russian attack submarine in the Philippines' exclusive economic zone in the South China Sea was "very worrisome".

Last week, the Philippine military responded to a situation in the South China Sea that sparked alarm within the country. A Russian submarine passed through the Philippine exclusive economic zone (EEZ),

The presence of this Russian submarine, and what will likely be others, could very well be a sign that Russia is expanding its military presence in an already hotly contested Indo-Pacific, and that could spell trouble for the United States and its allies,