Oil tankers are steering clear of the Strait of Hormuz ahead of a US blockade later on Monday following failed peace talks between the US and Iran over the weekend, shipping data showed.President Donald Trump said on Sunday the US Navy would start blockading the Strait of Hormuz, raising the stakes after marathon talks with Iran failed to reach a deal to end the war, jeopardising a fragile two-week ceasefire.US Central Command said US forces would begin implementing the blockade of all maritime traffic entering and exiting Iranian ports at 10 a.m. ET (1400 GMT) on Monday.It would 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,” it said in a statement on X.US forces would not impede freedom of navigation for vessels transiting the Strait of Hormuz to and from non-Iranian ports, and additional information would be provided to commercial mariners through a formal notice prior to the start of the blockade, it said.Iran’s Revolutionary Guards said on Sunday that any military vessels attempting to approach the Strait of Hormuz would be considered a violation of the ceasefire and be dealt with harshly and decisively.Pakistan-flagged tankers Shalamar and Khairpur entered the Gulf on Sunday, data from LSEG and Kpler showed.The Aframax tanker Shalamar is heading to the United Arab Emirates on Monday to load Das crude while the Panamax-sized Khairpur is heading to Kuwait to load refined products, the data showed.Pakistan National Shipping, which manages Shalamar, did not immediately respond to a request for comment outside of office hours.Liberia-flagged very large crude carrier (VLCC) Mombasa B, which also transited the strait earlier on Sunday, is ballasting in the Gulf, the data showed.Malta-flagged VLCC Agios Fanourios I, which tried to pass through the strait on Sunday to enter the Gulf to load Iraqi Basra crude for Vietnam, has since turned back and is now anchored near the Gulf of Oman, the data showed. The tanker plans to head to Iraq.Eastern Mediterranean Maritime, which manages the Agios Fanourios I, and CMB.TECH NV, the manager for the Mombasa B, did not respond to requests for comment outside office hours.Despite the stalemate, three supertankers fully laden with oil passed through the Strait of Hormuz on Saturday, shipping data showed. They appeared to be the first vessels to exit the Gulf since the ceasefire deal was struck last week.