A Saudi-led coalition intensified air strikes on Yemen early on Wednesday as the armed Houthi movement tightened its grip on the capital after it killed former president Ali Abdullah Saleh, who switched sides in the civil war.
Saudi Arabia and its allies launched dozens of raids on Houthi positions in Sanaa and nearby provinces, a day after Saleh's son vowed to take revenge.
Yemen's pro-Houthi Al Masirah television station said the coalition bombed Saleh's residence and other houses of his family members which are now controlled by the Houthis. Air strikes also hit northern provinces including Taiz, Haja, Midi and Saada, it added.
There was no immediate word on casualties.
The intervention by Ahmed Ali, a former leader of the elite Republican Guard once seen as a successor to his father, provided the anti-Houthi movement with a potential figurehead after a week of fighting that saw the Houthis rout Saleh's supporters.
But a day after Saleh supporters announced the deaths of his nephew Tareq, another top commander, and the head of his party Aref Zouka, many Sanaa residents hunkered indoors out of fear of a Houthi crackdown on the ex-president's many admirers.
Yemen's war, pitting the Iran-allied Houthis who control Sanaa against a Saudi-led military alliance backing a government based in the south, has unleashed what the United Nations calls the world's worst humanitarian crisis.
The proxy war between regional arch-rivals Saudi Arabia -- armed and furnished intelligence by the West -- and Iran has already killed more than 10,000 people, with more than two million displaced.
Political sources said the Houthis had arrested dozens of Saleh's allies and army officers affiliated with his party in and around the city. Several had been killed in the raids.
"There's a scary calm in the city," said Ali, a 47-year old businessman who declined to use his full name.
"People are reporting that there are many arrests and they are trying to shoot military men and (Saleh party) members."
Saleh had helped the Houthis win control of much of the north, including Sanaa, and his decision to switch allegiance and abandon the Houthis in the past week was the most dramatic change in three years of stalemated war.
But the Houthis swiftly crushed the pro-Saleh uprising in the capital and killed him. Top Houthi officials called his attempted putsch high treason backed by their Saudi enemies.
Several dozen women gathered in a main square holding Saleh's portrait and demanding his burial, eyewitnesses said, but were forcibly dispersed by Houthi supporters and ran in terror from the site.
The Houthi-controlled interior ministry distributed a video of dozens of seated barefoot men it said were pro-Saleh fighters detained in one of its party headquarters.
Media rights group Reporters Without Borders appealed for the release of 41 journalists it said have been held "hostage" by the group since it overran the headquarters of the Saleh-owned al-Yemen al-Youm TV station on Saturday.
THREAT OF FAMINE
In a sign of support and defiance, tens of thousands of Houthi supporters staged a rally in Sanaa on Tuesday to celebrate the death of Saleh. They chanted slogans against Saudi Arabia and its allies.
Nearly a million have been hit by a cholera outbreak and famine threatens much of the country.
The United Nations says millions of people may die in one of the worst famines of modern times, caused by warring parties blocking food supplies.
The UN Secretary-General Special Envoy for Yemen, Ismail Ould Cheikh Ahmed, called on all parties to show restraint in a briefing to the Security Council.
"Increased hostilities will further threaten civilian lives and exacerbate their suffering," he said.
U.S. Defense Secretary Jim Mattis said on Tuesday that the killing of Saleh would, in the short term, likely worsen an already dire humanitarian situation in the country.
Mattis, speaking with reporters on a military aircraft en route to Washington that his death could either push the conflict towards U.N. peace negotiations or make it an "even more vicious war."
The commander of Iran's Islamic Revolution Guards Corps (IRGC), Major General Mohammad Ali Jafari, said Yemen's enemies had been behind Saleh's armed uprising and praised what he called the Houthis' swift quashing of the "coup against the holy warriors", the semi-official Fars news agency reported.
The death of Saleh, who once compared ruling Yemen to dancing on the heads of snakes, deepens the complexity of the multi-sided war.
Much is likely to depend on the future allegiances of his loyalists, who had previously helped the armed Houthi group, which hails from the Zaidi branch of Shi'ite Islam that ruled a thousand-year kingdom in northern Yemen until 1962.