It was the second such warning in two days. On Tuesday, Vice President Mohamed Reza Rahimi threatened to close the strait, cutting off oil exports, if the West imposes sanctions on Iran's oil shipments.
"Closing the Strait of Hormuz is very easy for Iranian naval forces," Adm. Habibollah Sayyari told state-run Press TV. "Iran has comprehensive control over the strategic waterway," the navy chief said.
The threats belie Iranian concern that the West is about to impose new sanctions that could target Tehran's vital oil industry and exports.
Western nations are growing increasingly impatient with Iran over its nuclear program. The U.S. and its allies have accused Iran of using its civilian nuclear program as a cover to develop nuclear weapons. Iran has denied the charges, saying its program is geared toward generating electricity and producing medical radioisotopes to treat cancer patients.
With concern growing over a possible drop-off in Iranian oil supplies, a senior Saudi oil official said Gulf Arab nations are ready to step in if necessary and offset any potential loss of Iranian crude in the world markets.
Iran is the second largest OPEC oil producer, with an output of about 4 million barrels of oil a day. It relies on oil exports for about 80 percent of its public revenues.
Iran has adopted an aggressive military posture in recent months in response to increasing threats from the U.S. and Israel that they may take military action to stop Iran's nuclear program.
The navy is in the midst of a 10-day drill in international waters near the strategic oil route. The exercises began Saturday and involve submarines, missile drills, torpedoes and drones. The war games cover a 1,250-mile (2,000-kilometer) stretch of sea off the Strait of Hormuz, northern parts of the Indian Ocean and into the Gulf of Aden, near the entrance to the Red Sea as a show of strength and could bring Iranian ships into proximity with U.S. Navy vessels in the area.
Iran scored a victory earlier this month after it captured an American surveillance drone almost intact. Later, it went public with its possession of the RQ-170 Sentinel to trumpet the downing of the drone as a feat of Iran's military in a complicated technological and intelligence battle with the U.S.
American officials have said that U.S. intelligence assessments indicate that Iran neither shot the drone down, nor used electronic or technology to force it from the sky. They contend the drone malfunctioned.