A brief video clip showed two missiles being fired simultaneously in the darkness.
The report came hours after Secretary of State Condoleezza Rice warned Iran that Washington will not back down in the face of threats against Israel.
"We are sending a message to Iran that we will defend American interests and the interests of our allies," Rice said Thursday in Georgia at the close of a three-day Eastern European trip.
Among the missiles Iran said it tested Wednesday was a new version of the Shahab-3, which officials have said has a range of 1,250 miles and is armed with a 1-ton conventional warhead.
That would put Israel, Turkey, the Arabian peninsula, Afghanistan and Pakistan all within striking distance.
Wednesday's missile tests were conducted at the Strait of Hormuz, a strategic waterway at the mouth of the Persian Gulf through which up to 40 percent of the world's oil passes. Iran has threatened to shut down traffic in the strait if attacked.
Another Iranian state channel, Press TV, quoted a senior Republican Guard commander Thursday as saying Iran would maintain security in the Strait of Hormuz and the larger Gulf.
Gen. Mohammad Hejazi, chief of the Guards' joint staff, called the missile tests a "defensive measure against invasions," according to the channel's Web site.
Iran will not jeopardize the interests of neighboring countries, he said without elaborating.
Oil prices jumped on news of Wednesday's tests, rising $1.44 to $137.48 a barrel in electronic trading on the New York Mercantile Exchange.
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