SANAA, Yemen -- Saudi-led airstrikes hit weapons caches held by Iran-backed Shiite rebels, causing explosions Monday in Yemen's capital that killed at least 19 people and buried scores of others under the rubble of flattened homes.
The U.S. Navy, meanwhile, has dispatched the aircraft carrier USS Theodore Roosevelt toward the waters off Yemen to join other American ships prepared to intercept any Iranian vessels carrying weapons to the rebels, U.S. officials said.
After the coalition airstrikes, mushroom clouds rose over the mountainous outskirts of Sanaa, where the arms depots are located. The Fag Atan area has been targeted several times since March 26, the start of the air campaign against the Houthi rebels.
The blasts -- among the most powerful in Sanaa since the airstrikes began -- deposited a layer of soot on the top floors of buildings in the Yemeni capital and left streets littered with glass. Anti-aircraft fire rattled in response.
Saudi Arabia and several of its allies, mainly Gulf Arab countries, have been trying to drive back the rebels, who seized Sanaa in September and have overrun many other northern provinces with the help of security forces loyal to former President Ali Abdullah Saleh. The U.S. supports the Saudi campaign.
The Houthis and Saleh's forces have also advanced on the southern port of Aden, Yemen's main sea hub, forcing President Abed Rabbo Mansour Hadi to flee the country last month. The Houthis and their allies have been trying to take over Aden for weeks.
The announcement that the USS Theodore Roosevelt is heading for the region comes amid reports that a convoy of Iranian ships may be headed toward Yemen to arm the Houthis.
Navy officials said Monday that the Roosevelt was moving through the Arabian Sea.
White House spokesman Josh Earnest would not comment specifically on any Navy movements in Yemeni waters but said the U.S. has concerns about Iran's "continued support for the Houthis.
"We have seen evidence that the Iranians are supplying weapons and other armed support to the Houthis in Yemen. That support will only contribute to greater violence in that country. These are exactly the kind of destabilizing activities that we have in mind when we raise concerns about Iran's destabilizing activities in the Middle East."
There are about nine U.S. ships in the region, including cruisers and destroyers carrying teams that can board and search other vessels. The U.S. officials spoke on condition of anonymity because they were not authorized to discuss the ship movement on the record.
The U.S. Navy generally conducts consensual boardings of ships when needed, including to combat piracy around Africa and the region. U.S. naval personnel have not boarded any Iranian vessels since the Yemen conflict began.
Western governments and Sunni Arab countries say the Houthis get their arms from Iran. Tehran and the rebels deny that, though the Islamic Republic has provided political and humanitarian support to the Shiite group.
One of Monday's airstrikes hit close to the Iranian Embassy, shattering windows but causing no casualties among the staff, Iranian state TV reported. Iran summoned the kingdom's envoy in Tehran in protest.
Deputy Foreign Minister Hossein Amir Abdollahian warned the Saudis to abide by their international obligations and respect diplomatic missions, the report said, adding that it held Riyadh responsible for the safety of its mission in Sanaa.
In a column in Monday's New York Times, Iranian Foreign Minister Mohammad Javad Zarif called for a regional dialogue and said "Yemen would be a good place to start."
In the Fag Atan area, a 10-house village was destroyed in the explosions, according to witnesses who spoke on condition of anonymity because they fear for their safety. While some villagers had fled earlier, those who remained were believed to have been killed, they said.
Mohammed Saleh said he and his family fled in a friend's car after his was destroyed in the strike. He said hospitals were packed with wounded.
Houthi spokesman Mohammed Abdel-Salam denounced the airstrikes as a "crime that exposed the hatred and envy" of the Saudi-led coalition.
A Yemeni official said the airstrikes were intended to destroy Scud missiles known to be in the area. Medical officials said 19 bodies were taken to hospitals but that many were buried under the debris and the death toll was likely to rise.
The official and the medics spoke on condition of anonymity because they were not authorized to talk to media.
The Al-Masirah TV network, which is run by the Houthis, as well as the rebel-controlled Interior Ministry said at least 30 people were killed and hundreds were wounded. The casualty figures could not be independently confirmed.
Fighting intensified in Aden on Monday, with Houthis and Saleh loyalists battling youth militias and forces loyal to Hadi, who is in exile in Saudi Arabia. Clashes were underway near the Aden airport and in the central al-Arish district, witnesses said, speaking on condition of anonymity because they feared for their safety.
Coalition airstrikes targeted an Aden hotel suspected of being used by the Houthis and allied forces. All land lines and communications were cut amid the fighting.
Elsewhere, Saudi Arabia's Interior Ministry said a border guard was killed and two others were wounded from gunfire and mortar fire Sunday night from inside Yemen. The border guards were in the kingdom's southern province of Najran, the ministry said. It did not specify who the attackers were.
Saudi troops have been boosted along the mountainous border provinces of Najran and Jizan. Since the airstrikes began, Saudi soldiers and Houthis have frequently exchanged mortar fire and sniper fire from across the border.
At least six other Saudi soldiers have been killed this month in clashes with the Houthis along the border.
On Monday, the Saudi ministry said security would be increased at shopping centers and oil facilities across the country after it received information about possible threats to the sites.
"Precautionary measures were put in place to protect against an attempt by militants to target the facilities, said Interior Ministry spokesman Maj. Gen. Mansour al-Turki.
At malls in Riyadh, extra security searches of bags have been in place since Saturday.
The security concerns prompted U.S. diplomatic missions in the kingdom to halt consular services for a week in March. Two police officers were killed in a drive-by shooting in Riyadh earlier this month.
Information for this article was contributed by Lolita C. Baldor, Aya Batrawy and Jim Kuhnhenn of The Associated Press.
A Section on 04/21/2015