A senior official in the Iran-allied Houthi movement said the movement of more U.S. warships into waters off Yemen escalates Washington's role in a Saudi-led campaign against the group and aims at tightening a "siege" on the country.
"The goal of the movement of American ships is to strengthen the siege imposed on Yemen and put the Yemeni people under collective punishment," Houthi politburo member Mohammed al-Bukhaiti told Reuters.
"This step increases the level of their participation in this war," he added.
The U.S. Navy sent the carrier USS Theodore Roosevelt and its escort cruiser, USS Normandy, from the Gulf into the Arabian Sea on Sunday. The ships join seven other U.S. warships in the waters near Yemen, which is torn by civil strife as Iranian-backed Houthi rebels battle forces loyal to the U.S.-backed president.
President Barack Obama said on Tuesday the U.S. government had sent "very direct messages" to Iran warning it not to send weapons to Yemen that could be used to threaten shipping traffic in the region.
In a televised interview on Tuesday on MSNBC's "Hardball," Obama said Washington had been "very straightforward" with Tehran about the issue.
"Right now their ships are in international waters. There's a reason why we keep some of our ships in the Persian Gulf region and that is to make sure that we maintain freedom of navigation," Obama said.
"What we've said to them is that, 'If there are weapons delivered to factions within Yemen that could threaten navigation, that's a problem," he added. "And we're not sending them obscure messages. We send them very direct messages about it."
U.S. Not in Direct Contact with Iranian Flotilla
However, 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.
Army Colonel Steve Warren, a spokesman for the Pentagon, also said he did not believe Navy warships patrolling the region had been in direct contact with the Iranian flotilla of nine cargo ships.
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 leader of Yemen’s Houthi militants vowed on Sunday not to surrender in the face of Saudi-led airstrikes, speaking for the first time since the Arab coalition's campaign against the group began on March 26, reports the Wall Street Journal.
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.