Iranian naval ships docked on Saturday in the Saudi port city of Jeddah on a mission to project the Islamic republic's "power on the open seas," the Fars news agency reported.
The supply ship Kharg and Shaid Qandi, a destroyer, docked in the Red Sea port in line with orders from Iran's supreme leader Ayatollah Ali Khamenei, it quoted navy commander Admiral Habibollah Sayari as saying.
"This mission aims to show the power of the Islamic republic of Iran on the open seas and to confront Iranophobia," he said, adding that the mission started several days ago and would last 70 to 80 days.
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The commander did not give other destinations.
Iran's navy has been boosting its presence in international waters since last year, deploying vessels in the Indian Ocean and Gulf of Aden on missions to protect Iranian ships from Somali pirates.
Tehran also sent two ships into the Mediterranean for the first time in February 2011 through the Suez Canal.
Ties between Iran and Saudi Arabia, which have long been strained, deteriorated in late 2011 following US allegations that a foiled plot to assassinate the Saudi ambassador to Washington had been hatched in Tehran.
Tehran has also called on Riyadh to reconsider its vow to make up for any shortfall in Iran's oil exports due to sanctions over its nuclear programme, saying Riyadh's pledge to intervene on the market was unfriendly.