That window has been scrapped, with the ships now authorized to dock between Feb. 26 and March 3, the Brazil's foreign ministry said.
A Brazilian military source confirmed that the federal government, via the foreign ministry, had shifted the dates and blocked the Iranian ships from docking.
"The Iranian ships could not come during this period."
A spokesperson for Brazil's foreign ministry said it was a "wrong assumption" to say Washington had pressured Brazil.
Lula recoiled at U.S. sanctions on Iran and has declined to choose sides in the Russia-Ukraine war, saying Brazil is neutral and wants dialogue to reach peace.