At least three children and more than 60 adults have reportedly been killed in airstrikes in Yemen, according to the Save the Children charity.
The Saudi-led coalition is believed to be behind the offensive, having stepped up operations on areas held by the Iranian-backed Houthi rebels.
One of the targets where at least 60 people died and another 100 were injured was a prison run by the Houthis near the northern city of Saada, according to the Red Cross.
Doctors Without Borders said the number of injured was “around 200”.
Aid workers continue to clear the rubble with more casualties expected to be discovered.
Save the Children said most of those killed were detained migrants held in the jail.
The children who died were said to have been playing on a nearby football field when missiles struck the port town of Hudaida on Friday morning.
The airstrikes also damaged a telecommunications centre in Hudaida, which resulted in a nationwide internet blackout.
The internet disruption started at around 1am local time and affected TeleYemen, the state-owned monopoly that controls internet access in the country and is now run by the Houthis, according to NetBlocks.
Over 12 hours later, the internet remained down.
The Norwegian Refugee Council said the strike was “a blatant attack on civilian infrastructure that will also impact our aid delivery”.
More airstrikes hit near Sanaa, Yemen’s capital, which has been held by the Houthis since late 2014.
“The initial casualties report from Saada is horrifying,” said Gillian Moyes, Save the Children’s country director in Yemen.
“Migrants seeking better lives for themselves and their families, Yemeni civilians injured by the dozens, is a picture we never hoped to wake up to in Yemen.”
The Saudi-led coalition acknowledged carrying out “accurate air strikes to destroy the capabilities of the militia” around Hudaida’s port.
Earlier this week the Houthis claimed responsibility for suspected drone attacks in Abu Dhabi, which killed at least three people and injured at least six others.