In a sign of the worsening conflict in a new theatre, the United States tightened its travel warning for Saudi Arabia, banning government employees from travelling within 32 kilometres of the Yemen border.
The Houthis, who since last week have swept through Yemeni towns along the Red Sea coast and seized islands in the Bab el-Mandeb strait at its mouth, released battlefield video overnight of fighters seizing armoured vehicles from Saudi-backed forces.
Warplanes flew overhead and huge explosions billowed into the sky from desert dunes.
Houthi military spokesman Yahya Saree said the Houthis had shot down a Saudi F-15 fighter jet.
No immediate evidence was presented and Saudi officials did not immediately respond to emails seeking comment.
Saree said the Saudis had carried out up to 450 air strikes on Yemen this week.
Officials in the Saudi-backed government that controls southern Yemen have acknowledged that their forces and those of Saudi Arabia were conducting air strikes on Houthi positions, though Riyadh itself has not confirmed them.
The Houthis have fired repeatedly into Saudi Arabia over the past week causing alarms in cities in the south and west.
An attack blamed on Iran-aligned fighters in Iraq last week also knocked out Saudi Arabia’s East-West Pipeline, the main route used to divert exports away from the blockaded Strait of Hormuz.
Riyadh said its air defences had shot down a Houthi drone south of Mecca on Tuesday before it entered prohibited airspace over the holy city, an attack it said crossed a “red line” of threatening shrines sacred to all Muslims.
Saree denied the Houthis had targeted Mecca and said the Saudi reports were a set-up for propaganda purposes.
The extension of the war into Yemen threatens to worsen the global energy supply shortage caused by the six-month-old US-Israeli war on Iran, which has disrupted shipping through the Strait of Hormuz.
The price of Brent crude hovered around US$108 a barrel on Wednesday, close to its highest level since May.
The politically sensitive average retail price of diesel fuel in the United States hit another all-time high above US$6.30 a gallon for the first time.
Traders say a prolonged closure of Saudi Arabia’s East-West Pipeline could cut off as much as four percent of global oil supply.
Saudi Arabia has not said when operations might resume, but US Energy Secretary Chris Wright told CNBC on Tuesday that crude oil should be flowing through the pipeline within days. (Reuters)
