(CNN) -- A U.S. Navy minesweeper remained stuck in a reef teeming with endangered marine life off the Philippines on Sunday, prompting an American commander to apologize and promise stepped-up efforts to prevent further damage. The USS Guardian ran aground early Thursday in the Tubbataha Reef, about 80 miles east-southeast of Palawan Island in the Sulu Sea, the U.S. Navy reported. All 79 sailors were evacuated from the 224-foot ship. Hazardous weather and rough seas have hindered efforts to survey the empty Guardian and the surrounding area, though the Navy acknowledges damage to the reef. "As a protector of the sea and a sailor myself, I greatly regret any damage this incident has caused the Tubbataha Reef," said Vice Adm. Scott Swift, the U.S. 7th Fleet commander, in a report posted Sunday on a Navy website.
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A U.S. Navy minesweeper got stuck Thursday in a sensitive reef off the Philippines
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It remained there Sunday, with no sailors aboard and its damage still not surveyed
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A U.S. navy official says, " I greatly regret any damage this ... caused the Tubbataha Reef"
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The reef, a World Heritage Site, contains threatened and endangered marine species
Home to a vast array of sea, air and land creatures, as well as sizable lagoons and two coral islands, @placeholder is a UNESCO World Heritage site.