Archaeologists have found five well-preserved Roman shipwrecks deep under the sea off a small Mediterranean island, with their cargo of vases, pots and other objects largely intact, officials said Friday.

The ships are submerged about 330 to 490 feet off Ventotene, a tiny island that is part of an archipelago off Italy's west coast between Rome and Naples.

The ships, which date from between the 1st century B.C. and the 4th century, carried amphorae — vases used for holding wine, olive oil and other products — as well as kitchen tools and metal and glass objects that have yet to be identified, Italy's Culture Ministry said. The spot was highly trafficked, and hit by frequent storms and dangerous sea currents.

The discovery is part of a new drive by archaeological officials to scan deeper levels of the sea and prevent looting of submerged treasures.

Discoveries of shipwrecks are not unusual in the Mediterranean, but these ships are far better preserved than most, which are often found scattered in fragments, said Annalisa Zarattini, the head of the ministry's office for underwater archaeology. Because the ships sank at a deeper lever than most known wrecks, they were not exposed to destructive underwater currents, she said.

The ships also sank without capsizing, allowing researchers to observe their cargo largely as it had been loaded, Zarattini said.

"It is like an underwater museum," Zarattini said. The finding also sheds light on the trade routes of ancient Rome, marking the area as a major commercial crossroads, she said.

Treasure hunters usually dive down to about 30 meters (about 100 feet) underwater, but new and fast-spreading technology will make it increasingly easier for them to dive deep, Zarattini said. "It's important to arrive first," she added.

The ships were found during explorations concluded earlier this month by the ministry and the AURORA Trust, a U.S. group that gathers maritime researchers and provides equipment to explore the sea.

The researchers used sonar technology to provide imagery of the seabed and then employed remotely operated vehicles, the Culture Ministry and the AURORA Trust said.

The oldest of the ships has a cargo of wine amphorae from southern Italy, some stacked in their original position, AURORA said. Another one was carrying moratoria, large bowls used to grind grains. Another was loaded with African amphorae carrying garum, a fish sauce that was a delicacy in ancient Rome.

The largest wreck measures more than 20 meters (65 feet).

A handful of objects were taken out to be studied and will be put on display in Ventotene.