UNITED NATIONS — The U.N. children's agency is warning that unless the world focuses on the most disadvantaged youngsters in its new goals to fight global poverty over the next 15 years, millions more children will die from mostly preventable causes and be chronically undernourished.

UNICEF's "Progress for Children" report released Monday night said that despite significant achievements since world leaders adopted the Millennium Development Goals in 2000, unequal opportunities have left millions of youngsters to die young or live in poverty without an education.

UNICEF Executive Director Anthony Lake said those goals have helped achieve tremendous progress, "but they also showed us how many children we are leaving behind."

"If the global community allows the current trends to continue we will fail millions of children," he warned in a conference call.

On the plus side, since 1990, under-five mortality dropped by more than half, chronic malnutrition among children under five decreased by 41 percent, and millions more children have gotten a primary school education. But on the negative side, six million children still die every year before their fifth birthday and 58 million children don't go to primary school.

Lake urged world leaders who will meet in September to put the planet's poorest children at the heart of new development goals for 2030 that they will adopt.

He said this can reduce the cycle of poverty in which yesterday's poor, uneducated children become today's poor, uneducated adults who pass on that same life to their children.

The report warned that continued failure to reach these children can have dramatic consequences.

At current rates of progress, given projected population growth, UNICEF estimated that 68 million more children under five will die from mostly preventable causes by 2030 — and an estimated 119 million children will still be chronically malnourished by that date.