The Pentagon said on Tuesday the presence of a large convoy of Iranian cargo ships in the Arabian Sea was one factor in the U.S. decision to deploy additional warships in the waters off war-torn Yemen but was not the primary reason for the move.
Warren dismissed reports the carrier USS Theodore Roosevelt and cruiser USS Normandy had been deployed to the region to intercept Iranian ships carrying arms to Iranian-backed Houthi rebels fighting forces loyal to the U.S.-backed Yemeni president.
"Many have asked me whether or not they (the U.S. warships) are there because of the Iranian ship convoy or flotilla that is also in the area," Warren said. "That is certainly one of the factors. That is not the reason they are there."
He said the United States
did not know what the Iranian cargo ships were carrying and declined to say whether the U.S. warships would stop and board Iranian vessels if they attempted to enter Yemeni territorial waters.
"I'm not going to telegraph anything," Warren said.
Warren said U.S. warships were in the Gulf of Aden area "because of the deteriorating security situation in Yemen" and the need to ensure freedom of navigation through the zone, which is vital to oil shipping.
Asked how the Houthis could pose a threat to maritime security when they do not have a navy, Warren pointed to Libya, where rising conflict has prompted refugees to pack aboard boats that later capsized in the Mediterranean.
"It's difficult to predict the future so what we need to have are options," Warren said. "We have to preserve and to create options for ourselves should the deteriorating security situation get to a point that ... maritime security is threatened."
The Shi'ite Muslim Houthis sidelined the central government after seizing the capital Sana'a in September and occupying a broad swath of Yemen, which borders oil giant Saudi Arabia.
A Saudi-led coalition has launched an air campaign to try to stop the advance of the Houthis. The Saudis say their aim is to restore President Abd-Rabbu Mansour Hadi.
The UN Security Council imposed an arms embargo on the Houthi rebels, and the Saudi navy has imposed a naval blockade around Yemen.
(Reporting by David Alexander; Editing by Cynthia Osterman)