The government will nominate a group of ancient monuments in Okinawa Prefecture for inclusion on the World Heritage List, the Foreign Ministry said in a statement Wednesday.

The monuments include the ruins of Shuri Castle, home of the former regional kings in the current capital of Naha, and the ruins of Nakagusuku Castle, which encompass the villages of Kitanakagusuku and Nakagusuku, the statement said.

The government plans to officially nominate the sites, which occupy a total area of 54.9 hectares, to the Paris-based U.N. Educational, Scientific and Cultural Organization by July 1, it said.

The castle ruins are on Okinawa's main island. The Cultural Affairs Agency said earlier the two castles display the distinctive characteristics of the culture of Ryukyu, as Okinawa was formerly known.

In the mid-14th century, disputes by local rulers split the island into three kingdoms. In 1429, the island was unified by a king of the Sho dynasty, and remained under their rule for four centuries until Japan took control.

Nakagusuku Castle was constructed during the period of division.

Shuri was the home of Ryukyu kings for 500 years until the island became a Japanese prefecture in 1879. It was destroyed in the Battle of Okinawa near the end of World War II, but a replica was later built.