U.S. to start blockading all ship traffic in Gulf of Oman, Arabian Sea on Monday

Lead

US Central Command (CENTCOM) has announced it will begin enforcing a blockade of all maritime traffic entering or departing Iranian ports and coastal areas, effective Monday, according to notices to seafarers reported by multiple news agencies. The measure, which covers the Gulf of Oman and the Arabian Sea east of the Strait of Hormuz, follows the breakdown of US-Iran negotiations in Islamabad over the weekend.

According to a CENTCOM note cited by Reuters and reported by TASS and Yonhap, the blockade will take effect at 2:00 p.m. GMT (10:00 a.m. Washington time) on Monday. The notice states that any vessel entering or departing the blockaded area without authorization is subject to interception, diversion, and capture.

Coverage comparison

Reports from TASS, The Hindu, and Yonhap — drawing on official statements from CENTCOM and a note to mariners relayed through the UK Maritime Trade Operations (UKMTO) — are broadly consistent on the key details of the blockade. All describe a comprehensive restriction on vessels engaging with Iranian ports, oil terminals, or coastal facilities, regardless of flag.

The sources diverge slightly on the precise geographic scope. TASS reports that the restrictions apply to "the entirety of the Iranian coastline," including ports and oil terminals, and specifies that transit through the Strait of Hormuz to or from non-Iranian destinations will not be impeded. The Hindu's report quotes CENTCOM saying the blockade will be "enforced impartially against vessels of all nations entering or departing Iranian ports and coastal areas," including all Iranian ports on the Arabian Gulf and Gulf of Oman.

Yonhap's report frames the blockade as apparently aimed at pressuring Iran by restricting its oil exports, a critical source of revenue. Other outlets have not explicitly attributed a strategic motive.

Key Claims

• The blockade will apply to the entire Iranian coastline, including all ports and oil terminals, and will be enforced impartially against vessels of all nations, per CENTCOM notices reported by TASS and The Hindu.
• Transit through the Strait of Hormuz to or from non-Iranian ports will remain unrestricted, according to CENTCOM's notice as reported by TASS, The Hindu, and Yonhap.
• Humanitarian shipments — including food, medical supplies, and other essential goods — will be permitted, subject to inspection, according to the CENTCOM note reported by TASS.
• Any vessel entering or departing the blockaded area without authorization is subject to interception, diversion, and capture, as stated in the notice cited by Yonhap and TASS.
• The blockade follows several rounds of talks between US and Iranian delegations in Islamabad on April 11, led by Vice President JD Vance and Iranian Parliament Speaker Mohammad Bagher Ghalibaf, respectively. Both sides said no agreement was reached, per TASS.
• A single report from the BBC, relayed by TASS, says the USS Abraham Lincoln carrier strike group has entered the Gulf of Oman, approximately 200 km south of Iran's coast — the closest approach of a US vessel since the start of US strikes on Iran. This claim has not been independently confirmed by other sources.

Perspectives

US officials, as conveyed through CENTCOM's public statements, present the blockade as a lawful measure targeting Iranian port access while preserving freedom of navigation through international waters. The explicit exemption for non-Iranian transit in the Strait of Hormuz appears designed to address concerns about disrupting global oil shipments.

Iranian officials, as quoted in TASS's report on the Islamabad talks, have not commented publicly on the blockade, but the failure of negotiations suggests a hardening of positions. The Iranian delegation emphasized disagreements on a long-term settlement, with no new talks announced.

Regional and international observers, as hinted in Yonhap's analysis, view the blockade as a significant escalation that could restrict Iran's oil exports and heighten tensions in a vital maritime chokepoint. However, the stated exemptions for humanitarian goods and neutral transit may aim to mitigate immediate economic impacts on third countries.