Yemen’s Shiite rebels have fired rockets and mortars into Saudi Arabia today, killing at least two civilians.
Five soldiers have reportedly been captured.
The offensive appears to show the insurgents’ ability to launch assaults despite weeks of air strikes targeting them.
Saudi Arabia’s state airline cancelled flights into the border area of Najran as schools closed early amid the attack.
Meanwhile, hundreds of families fled Aden after Houthis advanced into their neighbourhoods, firing indiscriminately as they took over surrounding, towering mountains.
In Najran, the shelling killed two Saudi civilians and damaged buildings, Yemeni tribal leaders said.
The state-run airline, Saudia, said flights to and from the area would be suspended until further notice.
The tribal leaders also said the Houthis captured five Saudi soldiers in unclear circumstances. Saudi media and defence officials had no immediate comment on the report.
Saudi state television reported schools closed early and quoted Saudi Brig Gen Ahmed Asiri as saying that the assault reflects the state of “Houthi chaos”.
He added that Saudi Apache attack helicopters returned fire. Aired footage showed burned cars burnt, smouldering houses and debris covering nearby roads.
Last week, three Saudi troops and dozens of rebels were killed in the fighting there.
The assault today underscored how the Iranian-allied Houthis are still capable of launching major operations despite more than a month of Saudi-led air strikes targeting them and their allies – military units loyal to former president Ali Abdullah Saleh.
A Saudi-led coalition began bombing the Houthi rebels and their allies on March 26 in support of exiled President Abed Rabbo Mansour Hadi’s embattled government.
The air strikes and fighting on the ground have killed hundreds and displaced at least 300,000 Yemenis.