Airstrikes over Yemen's capital last night left worried citizens seeking shelter in basements as the Saudi-led coalition pounded Houthi rebel positions.
Suze van Meegen, Sanaa-based protection and advocacy adviser for the Norwegian Refugee Council, said Monday that the violence left aid workers trapped inside their homes and was "completely paralysing humanitarian operations."
"No one is safe in Sanaa at the moment. I can hear heavy shelling outside now and know it is too imprecise and too pervasive to guarantee that any of us are safe," she said.
Schools and shops in Yemen's capital were closed on Sunday as clashes erupted in Sanaa following the collapse of a rebel alliance.
Residents of Sanaa neighbourhoods said they had barricaded themselves in their homes to avoid snipers and shelling as clashes flared up around key ministries where the two sides had been working together just days before.
Yemen's rebel alliance, who has been in control of Sanaa since 2014, has unravelled in recent days with security forces reporting some 60 combatants killed in clashes between the two sides across the capital, including at the international airport.
"The night was tough," Robert Mardini, regional director of the International Committee of the Red Cross, posted on his Twitter account. "Massive urban clashes with heavy artillery and airstrikes. Yemenis stuck in their homes, too scared to go out. Reduced access to water, health care, food and fuel."
Civilians living in the Yemeni capital are largely cut off from the outside world.
Reports suggest that at least 100 people have been killed and more than 300 wounded in the fighting which began on Wednesday.
Saudi Arabia and its allies began their campaign against the impoverished country in March 2015 fighting the Houthi rebels, later expanding into ground operations.
The fragile alliance between the Iranian-backed Houthis and Saleh loyalists, who joined ranks in 2014 to seize Sanaa has since been rocked with infighting.
The Yemen war has claimed more than 10,000 lives since the Saudi-led campaign began. The country is now facing what the United Nations has described as the world's worst humanitarian crisis.