Iran says it is closing Strait of Hormuz over Israeli attacks on Lebanon

The Iranian armed forces announced Saturday they will close the Strait of Hormuz — just three days after it reopened — alleging America's failure to rein in Israeli attacks on Lebanon violates the new ceasefire deal.

Why it matters: This is the first big crisis between the U.S. and Iran since signing a memorandum of understanding to end the war earlier this week.

• It takes place as President Trump's envoys are already in Switzerland ahead of a potential first round of nuclear negotiations planned for Sunday.
• The Iranian delegation headed by speaker of parliament Mohammad Bagher Ghalibaf and foreign minister Abbas Araghchi is expected to arrive in Switzerland on Saturday.

State of play: A senior U.S. defense official said the U.S. military is still not seeing any Iranian military movements on the ground that reflect a potential "closing" of the strait.

• "Safe passage through the international waterway remained intact today as 55 merchant ships transited, moving large amounts of cargo and more than 17 million barrels of oil to global markets," U.S. CENTCOM said Saturday.
• CENTCOM spokesman Capt. Tim Hawkins told Axios that "Iran does not control the Strait of Hormuz. Traffic continues to flow, and U.S. forces are monitoring the situation to ensure this remains the case."
• Prior to the war, about 130 ships transited the strait each day, per the Congressional Research Service.

What they're saying: Shortly before Araghchi announced he is traveling to Switzerland, the Khatam al-Anbiya central headquarters of the Iranian armed forces announced it was closing the Strait of Hormuz.

• "In light of the United States' clear bad faith and breach of its commitment to implement the first clause of the memorandum of understanding for ending the war, and in response to the continuous and ongoing violations of the ceasefire by the Zionist regime in southern Lebanon, it is hereby announced that the Strait of Hormuz will be closed to maritime traffic."
• The Iranian military said this is "the first step" in responding to alleged violations of the ceasefire. "Should the aggression continue, further measures have been planned and will be implemented to compel the enemy to abide by and carry out its obligations."
• Shortly after that, the Iranian Revolutionary Guards Corps navy said the strait "is closed to all vessels" and warned ships not to approach.