The commander of NATO's naval forces says Iranian threats to close a strategic Persian Gulf waterway are a fantasy and the international passage cannot be blocked.

Italian Navy Vice Admiral Maurizio Gemignani is visiting the oil-rich Gulf state of Kuwait.

He said Tuesday that he considers the threats Iran has made to close the Strait of Hormuz a "fantasy" and international passages cannot closed down.

Iran has warned that it would close the strait if the United States attacks it over Tehran's disputed nuclear program.

About 40 percent of the world's oil passes through the strait.

Three NATO ships arrived in Kuwait on Tuesday to promote military cooperation.