Three Iranian tankers loaded with crude oil have passed the US blockade line in the Gulf of Oman, ship-tracking data shows.

Two were broadcasting their locations as they crossed and a third appeared to switch on its location tracker just past the line.

Despite President Donald Trump announcing on Sunday the "immediate removal" of the blockade of Iranian ports, US naval forces later confirmed it would remain in effect until the deal with Iran was signed. This is expected to take place in Switzerland on Friday.

"This a sign that Iran is confident the blockade is over, even if the US has insisted it will be in place until Friday," Michelle Wiese Bockman, senior analyst at Windward Maritime Intelligence, told BBC Verify.

The three Iran-flagged tankers, Diona, Hero II and Sonia I, are all owned by the National Iranian Tanker Company which has been sanctioned by the US Treasury, as have the ships themselves.

Iran has been subject to long-term US sanctions in response to fears the country is developing nuclear weapons, its support for groups designated by Washington as terrorist organisations, and alleged human rights abuses.

Data from MarineTraffic shows Hero II and Sonia I left Iran's Chabahar port on Tuesday, where several other Iranian tankers are currently anchored, and sailed past the US blockade line into the Arabian Sea in the early hours of Wednesday morning.

Diona began broadcasting its location just past the US blockade line, which stretches from the eastern tip of Oman to the coast of Iran, yesterday.

Maritime intelligence firm Windward says this is the first time any of these Iranian tankers have broadcast their locations since March and, if they make it to their destination, will be Iran's first oil exports for two months, according to TankerTrackers.com.

The three ships are carrying a combined total of 3.8 million barrels of crude oil, according to TankerTrackers.com. They are currently not broadcasting their planned destinations.

The US blockade has cut Iran's crude exports to the lowest amount in six years at 260,000 barrels per day in May, less than a fifth of the 2025 average of 1.67 million barrels per day, data from maritime intelligence firm Kpler shows.

The US had said early in its blockade that enforcement could happen outside of the Gulf region and BBC Verify has previously covered American forces intercepting Iran-linked vessels in the Indian Ocean, thousands of miles from the Gulf.

Another crude oil tanker owned by NITC, Stream, is currently approaching the US blockade line and appears to be sailing towards Iran.

The unladen tanker has been circling off the Pakistani port of Karachi since 8 May, ship tracking data shows.

Since the announcement of the US deal with Iran, "Iranian-linked tankers and cargo ships have become noticeably more active globally," according to the campaign and monitoring group United Against Nuclear Iran (UANI).

Two other crude oil tankers owned by the National Iranian Tanker Company also began broadcasting their positions in the Strait of Malacca between Malaysia and Indonesia on Tuesday.

Both tankers, Dan and Sinopa, had not been seen on publicly available ship tracking platforms since early April and now appear to be sailing towards Iran.

"Iran is wasting no time getting its tankers back into circulation," said Bockman.

Additional reporting by Barbara Metzler