The claims followed an announcement from the US military that three Iranian crude oil tankers had been struck and destroyed. Washington said the vessels were targeted in retaliation for attacks on US warships and alleged efforts to finance Iranian regional proxies.
The competing claims have added to uncertainty surrounding commercial shipping through the strategic waterway, which carries a significant share of global oil supplies.
US Central Command said on Sunday that American forces had redirected 92 commercial vessels as part of a naval blockade of Iran. It also said three vessels had been disabled and two boarded during the operation.
Despite the military confrontation, US Energy Secretary Chris Wright said substantial quantities of oil were continuing to move through the Strait of Hormuz.
Wright said an average of about nine million barrels of oil a day were still passing through the waterway, a level he said should help ease pressure on global energy prices.