Philippine navy frigate Jose Rizal established radio contact with the Russian submarine, which confirmed its identity as UFA 490 and its intent. "The Russian vessel stated it was awaiting improved weather conditions before proceeding to Vladivostok, Russia," Trinidad said, without elaborating on why it was in the area.

Tensions between Russia and the Philippines escalated as the Philippine military deployed a navy ship and air force planes to shadow a Russian submarine in the South China Sea last week, security officials said.

President Ferdinand Marcos Jr. said on Monday the reported presence of a Russian submarine in the Philippine's exclusive economic zone (EEZ) in the South China Sea was "very worrisome". The Philippine Daily Inquirer newspaper reported on Monday that a Russian attack submarine surfaced inside Manila's EEZ last week,