Two Iranian naval vessels are expected to pass through Egypt's Suez Canal into the Mediterranean on Tuesday.
The ships had been scheduled to enter the canal on Monday but the passage was delayed for unexplained reasons.
The vessels, a frigate and a supply ship, are heading to Syria on what is said to be a training mission. The passage would be the first time Iranian warships have passed through the Suez Canal since the 1979 Islamic revolution that overthrew the Shah of Iran.
Egypt's new military rulers approved the transit of the two vessels on Friday, despite decades of strained relations with Iran.
Israel considers the passage a provocation. Israeli Prime Minister Benjamin Netanyahu accuses Iran of taking advantage of the current instability in the Middle East to expand its influence by sending ships through the canal.
Once in the Mediterranean the Iranian vessels are not expected to enter Israeli territorial waters.
The Convention of Constantinople, signed in 1888, guarantees the right of passage through the canal for all seagoing vessels, military or civilian, at all times.
Some information for this report was provided by AP, AFP and Reuters.