In the western city of Hudaydah, eight people were killed and 10 were wounded Tuesday when an artillery shell hit a market to the west of the Tuhayta district, according to a statement by the UN Office for the Coordination of Humanitarian Affairs, AFP reported.
The statement added that unconfirmed reports indicated a woman was killed and three children injured the next day when a house was hit in the northern province of Hajjah.
"These attacks are unconscionable," said the United Nations' humanitarian coordinator for Yemen, Lise Grande.
"The country is facing the worst food security crisis in the world and yet the killing continues. Parties to the conflict are obliged to do everything possible to protect civilians."
Forces loyal to the ex-Yemeni government have repeatedly violated a ceasefire in Hudaydah.
The statement said there have been 271 civilian casualties, including 96 fatalities, between Jan. 1 and Feb. 14 in Yemen.
Over 24 million Yemenis, more than three quarters of the country's population, are now dependent on some form of aid for survival, according to the UN.
At least 10,000 people – mostly civilians – have been killed and more than 60,000 wounded in the Saudi-led war on Yemen, according to the World Health Organization.
Human rights groups say the real figure could be five times as high.