Saudi-led Arab coalition air strikes have targeted Yemen's capital Sanaa, bombing the houses of political leaders in the Houthi movement and military bases.
Witnesses said Thursday's raids were the fiercest attack on the city of two million residents in more than five months of the war. There were no immediate reports of casualties.
"The sick people fled the hospital in terror," an official at a private hospital told the Reuters news agency.
"They were afraid the building would collapse from the non-stop bombing of the army bases nearby."
Mohammed Saleh, a Sanaa resident, said: "I've decided my family and I have to get out of Sanaa.
"There's nowhere left that's safe here, and neighbourhoods are getting bombed every single day."
Saudi border guard killed
Meanwhile, a Saudi border guard was shot dead on Thursday when his post came under fire from Yemen, the Saudi interior ministry said.
The post in the Jazan district "was subject to heavy fire from a mountainous area in Yemen," said a ministry statement carried by the official Saudi Press Agency.
The statement said his colleagues returned fire and the guard died before reaching hospital.
Saudi Arabia and other Arab states intervened in Yemen's civil war on March 26 to halt the nationwide spread of the Houthis, who seized Sanaa last year and forced the government into exile in Riyadh, after advancing on its southern stronghold of Aden.
Since a Houthi missile attack killed at least 60 Gulf Arab troops east of Sanaa last Friday, the coalition has stepped up its air strikes on the capital and increased its deployment of troops, which Yemeni officials say number a few thousand, ahead of an eventual push towards Sanaa.
Fear is spreading that a decisive battle there may wreak widespread destruction, as it has in the southern city of Taiz, where medical staff said 18 people were killed in an explosion in a residential area on Thursday, variously blamed on Houthi artillery shelling and Saudi-led air strikes.
The World Health Organisation says more than 4,500 people have been killed in Yemen since March 19.
Source: Reuters And AFP