By a media trick, Tehran proved its claim that closing the Strait of Hormuz is as "easy as drinking water," DEBKAfile reports. First thing Saturday morning, Saturday, Dec. 31, Iran’s state agencies "reported" long-range and other missiles had been test-fired as part of its ongoing naval drill around the Strait of Hormuz. Ahead of the test, Tehran closed its territorial waters.

For five hours Saturday, not a single warship, merchant vessel or oil tanker ventured into the 30-mile wide Hormuz strait, waiting to hear from Tehran’ that the test was over.

Instead, around 0900 local time, a senior Iranian navy commander Mahmoud Moussavi informed Iran’s English language Press TV that no missiles had been fired after all. "The exercise of launching missiles will be carried out in the coming days," he said.

For five hours therefore, world shipping obeyed Tehran’s warning and gave the narrow waterway through which one-fifth of the world’s oil passes, a wide berth. They stayed out of range of a test which, DEBKAfile’s military sources report, aimed to demonstrate for the first time that Shahab-3 ballistic missiles which have a range of 1,600 kilometers and other missiles, such as the Nasr1cruise marine missile, are capable of reaching Hormuz from central Iran.

The Moussavi statement was not aired on Iran’s Farsi-language media. It was not necessary; Tehran had demonstrated by this ruse that it could close the vital waterway for hours or days at any moment.

Friday night, shortly after Tehran reported the missile-firing test was to take place the next morning, Washington announced the $3.48 billion sale to the United Arab Emirates of 94 advanced THAAD missiles with supporting technology.

Like the $30 billion sale of 84 F-15 fighter jets to the Saudi Arabia announced this week, delivery dates were not specified. The first F-15s for Saudi Arabia are due some time in 2015. It must therefore be said that the announced sophisticated US arms sales to the Persian Gulf nations bear only tangentially on the current state of tension in the region around Iranian threats.

The Hormuz missile stratagem has given Tehran three advantages in its face-off with Washington and the Gulf Arab governments:

1. It gave credibility to the threats issued by Iranian military chiefs last week regarding free passage in the Strait of Hormuz and Western sanctions:

On Dec. 29, Navy commander Adm. Habibollah Sayari said it was "really easy" for Iran’s armed forces to shut the strait, adding "But today, we don’t need [to shut] the strait because we have the Sea of Oman under control and can control the transit."

The next day, Deputy Commander of the Revolutionary Guards Gen. Hossein Salami said the United States was not in a position to tell Tehran "what to do in the Strait of Hormuz. Any threat will be responded to by threat… We will not relinquish our strategic moves if Iran’s vital interests are undermined by any means."

2. For Tehran, closing the vital waterway to international traffic without firing a shot – even for a few hours – served to rebut the warning given by US Fifth Fleet spokeswoman Lt. Rebecca Rebarich on Dec. 29. She said: "Anyone who threatens to disrupt freedom of navigation in an international strait is clearly outside the community of nations: any disruption will not be tolerated."

It also addressed the dispatch of the USS John C. Stennis aircraft carrier through the strait into the Sea of Oman in proximity to Iran’s ten-day Velayati 90 naval drill. The Stennis, accompanied only by a single destroyer, demonstrated US confidence in its military muscle against any Iranian threat.

As the Stennis passed through the big US air base at al-Udeid, Qatar, went on high alert.

3. Tehran did not explain why its war game, designated in advance a display of Iranian naval and air control of the Strait of Hormuz and the Sea of Oman, suddenly morphed into a ballistic missile test; nor its postponement.

DEBKAfile’s military sources report that the Iranians were in fact sending a message to the Gulf rulers and the US bases on their soil that they would not escape missile retaliation for a possible US or Israel attack on the Islamic Republic’s nuclear facilities or harsh sanctions.