My apologies if the bunkers were always Albanian. I may have seen it misreported. There is history there, though. Here’s what I could find on Wikipedia.

During the Cold War between the Soviet Union and the United States, Albania relied heavily on the Soviet Union. During that time, the Soviets built a base for Whiskey-class submarines and a chemical/biological weapons plant on the island and surrounding areas. The island stationed around 3,000 soldiers during this period.[15][16] However, the Soviet-Albanian split in the early 1960s marked the end of the Soviet naval presence on Sazan.[13] After the fall of communism four submarines remained at Pasha Limani port in the bay of Vlore.[17] To this day, many Soviet-era gas masks can still be found scattered around the valley of the island.

The island now is uninhabited but there is a small joint Italian—Albanian naval base, of reportedly two soldiers, used mainly to counter contraband between southern Italy and Albania, as a training field for the British Royal Navy, and as shelter for boats in nearby Albanian waters.[18][17][19][15][16] There are approximately 3,600 nuclear bunkers that were built by Albania during the Cold War.[15] There is also a villa on the island belonging to the former communist defence minister Beqir Balluku. In 2010, the island’s surrounding sea waters, and those of adjacent Karaburun Peninsula were proclaimed a National Marine Park by the Albanian government.

https://en.wikipedia.org/wiki/Sazan#Post–World_War_II