Rebecca Grant, a U.S. national security analyst, told Fox News that pressure on Tehran in the wake of the blockade of Iran’s southern ports by the United States has, so far, become the most effective diplomatic tool in the course of this confrontation.

Grant said: “The Navy and other U.S. military forces control that region.”

She added: “The renewed blockade has put a great deal of pressure on the Islamic Republic, and this can be seen in the list of demands that are extremist and unacceptable to Tehran.”

Grant emphasized: “The U.S. Navy can continue this blockade for as long as necessary.”

She said: “Two aircraft carriers, the amphibious landing ship Bunker, various types of aircraft, and air-defense systems deployed at ground bases—this is the pressure that will make the difference.”

The U.S. national security analyst added: “We should be prepared for military options, but what the past weeks have shown is that the Islamic Republic cannot withstand the pressure resulting from an inability to sell oil.”

Grant also said: “The main terminal on Kharg Island, from which about 90 percent of Iran’s oil is loaded, has now effectively ceased operations.”