Nearly a decade into Yemen's brutal civil war, some 4.5 million of its children are not attending school, charity Save the Children says.

The figure underlines how precarious daily life remains in the Arabian Peninsula's poorest country, despite relative calm since an April 2022 ceasefire.

"Two in five children, or 4.5 million, are out of school, with displaced children twice as likely to drop out than their peers," the group said in a report.

"One-third of families surveyed in Yemen have at least one child who has dropped out of school in the past two years despite the UN-brokered truce," it added.

The conflict in Yemen began when Houthis seized the capital Sanaa in September 2014, prompting a coalition to prop up and forming of the internationally recognised government months later.

Economic insecurity amid the war has plunged two-thirds of Yemen's 33 million inhabitants below the poverty line, the charity said, while also displacing about 4.5 million people.

"Displaced children are twice as vulnerable to school dropouts," Save the Children said.

"Nine years into this forgotten conflict, we are confronting an education emergency like never before," said Mohammed Manna, Save the Children's interim country director in Yemen.

"Our latest findings must be a wake-up call and we must act now to protect these children and their future."

The report said 14 percent of families interviewed by the aid group pointed to insecurity as the reason behind their children dropping out.

But a larger majority — some 44 percent — pointed to economic reasons, in particular the need to support family incomes. Some 20 percent said they were unable to afford regular school costs.

"The impact of the education crisis on Yemen's children and their future is profound," the charity said.