The U.S. military has said that it will start a blockade of the Strait of Hormuz at 10 a.m. Eastern on Monday for vessels "entering or departing Iranian ports and coastal areas," as President Donald Trump reportedly weighs limited strikes on Iran following failed weekend negotiations.

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The blockade will be enforced in the Gulf of Oman and Arabian Sea east of the Strait of Hormuz and apply to all vessel traffic regardless of flag, Reuters reported, citing a note to seafarers from U.S. Central Command. The note warned that any vessel moving through the blockaded area without authorization is "subject to interception, diversion and capture," although the blockade will "not impede neutral transit passage through the Strait of Hormuz to or from non-Iranian destinations."

In response, Iran’s armed forces have warned that "no port in the Persian Gulf and the Sea of Oman will be safe" should the blockade take effect, calling it an "act of piracy," according to state broadcaster IRIB. Tehran will also not allow U.S. ships to pass through the Strait of Hormuz and will protect its territorial waters, IRIB reported.

The spokesperson for the National Security Commission of Iran’s parliament dismissed Trump’s blockade as "bluster," but stressed that Tehran would retaliate to what it considers to be an "act of war." Only by showing "respect" could the U.S. improve the current situation, Ebrahim Rezai said on social media, adding that Iran has "other cards that we have not used in the game." 

Iranian Parliament Speaker Mohammad Bagher Qalibaf also declared Sunday that Iran will not yield to threats. Addressing Trump directly on social media, Qalibaf stated, “If you fight, we will fight."

European leaders moved to show their detachment from Trump’s blockade. Spain and the United Kingdom said they would not be involved, while European Commission President Ursula von der Leyen has called on the "restoration of the freedom of navigation."