Iran has again threatened to close the Strait of Hormuz, this time using the excuse of a military exercise set for January 27.

According to Esmaeil Kowsari, a Iranian legislator who is a member of the parliament’s National Security and Foreign Policy Committee, the country’s elite Revolutionary Guards corp will launch the naval exercise.

Kowsari was quoted in a report published Saturday by the Mehr News Agency as saying the drill would be carried out with the aim of fine-tuning Iran’s ability to close the Strait of Hormuz “in the shortest possible time when the situation requires it.”

The Strait of Hormuz is the primary maritime waterway through which some 40 percent of the Western world’s oil supplies are shipped.

Iranian Defense Minister Brigadier General Ahmad Vahidi said the drills — dubbed the “Great Prophet” — will be the “greatest naval war games” ever conducted by the Revolutionary Guards, according to the hard-line Fars news agency.

The exercises have apparently been moved up; they were originally scheduled to take place in February, according to remarks by Admiral Ali Fadavi quoted by Fars on January 5.

The Islamic Republic made a similar threat last month as well. Both the United States and the United Kingdom responded with warnings that any attempt to close the waterway would be considered an act of war.

Meanwhile, the U.S. is proceeding with an embargo on Iranian oil imports and the European Union is set to discuss a similar sanction at its meeting set for January 30. The sanctions are intended to force Iran to comply with a United Nations mandate to cease its nuclear development activities, which the country has defied repeatedly, insisting its programs are meant for peaceful domestic purposes only.

However, the U.N. International Atomic Energy Agency has gathered concrete evidence making it clear that Iran’s intentions are anything but peaceful, and that its programs are aimed at developing a nuclear weapon of mass destruction.

Israel has warned the international community for nearly a decade of such an eventuality, and that time is running out to contain the threat.