Children look at graffiti painted by pro-Houthi activists on the wall of the Saudi embassy in Sanaa August 2, 2015. [Photo/Agencies]

LONDON - Months of brutal conflict in Yemen have killed or injured more than 1,000 children, and the number of young people recruited or used as fighters has soared, the United Nations children's agency UNICEF said on Wednesday.

Some 400 children have been killed and more than 600 injured - an average of eight casualties every day - since fighting escalated at the end of March, according to UNICEF.

A Saudi-led Arab coalition has been bombarding the Iranian-allied Houthi rebel movement - Yemen's dominant force - since late March in a bid to reinstate exiled President Abd-Rabbu Mansour Hadi, who has fled to Riyadh.

The war has killed more than 4,300 people, many of them civilians, and spread disease and hunger throughout the country.

More than 1.3 million people have been forced to flee their homes since March, and nearly 10 million children - 80 percent of the country's under-18 population - need urgent humanitarian aid, UNICEF said in a report released on Wednesday.