The briefing comes as the conflict has intensified into a wider war in the region.
Iranian media say the Revolutionary Guard has seized an oil tanker carrying 700,000 liters of 'smuggled fuel' in the Persian Gulf.
The Trump administration's new Pentagon chief says he aims to ensure a U.S. naval presence in the Persian Gulf that would deter Iran from threatening to stop or seize any American commercial ship.
Iran doesn't seem to want to tangle with a stronger U.S. military. Instead, Iran is poking and prodding its Western antagonists in ways apparently designed to avoid triggering war.
The brief standoff between British and Iranian naval vessels in the Strait of Hormuz on Thursday looks to renew concerns about the vulnerability of world energy supplies to tensions in the Persian Gulf region.
China's top diplomat has warned the United States against opening a "Pandora's box" in the Middle East after a recent flare-up in tension between Washington and Tehran.
A U.S. Navy patrol boat fired warning shots Tuesday near an Iranian vessel that came close to it during a tense encounter in the Persian Gulf, an American defense official said.
The Pentagon says it briefly lost contact with two small Navy craft in the Persian Gulf on Tuesday but has received assurances from Iran that the crew and vessels will be returned safely and promptly.
President Barack Obama has signed legislation that gives Congress the power to review and potentially reject a nuclear deal with Iran.
Defense Secretary Chuck Hagel has ordered an aircraft carrier -- the USS George H.W. Bush -- to move from the northern Arabian Sea to the Persian Gulf as President Barack Obama considers possible military options for Iraq.