As the US government noted, this move aims to:
Send a clear and unmistakable message to the Iranian regime that any attack on United States interests or on those of our allies will be met with unrelenting force
The country also clarified that it is not seeking war with the Iranian regime, but it is 'fully prepared to respond to any attack, whether by proxy, the Islamic Revolutionary Guard Corps, or regular Iranian forces.'
Before this move, in the beginning of the month, the US State Department announced that the Significant Reduction Exemptions (SREs) granted last November to eight countries by the US for Iranian crude oil imports will not be renewed and expired on 2 May 2019.
Namely, China, India, Italy, Greece, Japan, South Korea, Taiwan, and Turkey, received waivers in order to continue to import limited amounts of Iranian crude oil.
For this reason, Iran threatened to block the Strait of Hormuz if it was not allowed to use the strategic waterway through which around a fifth of oil that is consumed globally passes.
The Strait of Hormuz is crucial shipping route that links Middle East oil producers to markets in Asia, Europe, North America and beyond. But it has been at the heart of regional tensions for decades, Reuters reports.