WASHINGTON, June 10 -- The World Bank on Tuesday lowered its projection for this year's global economic outlook, as developing countries are heading for "disappointing growth," while high-income countries are gaining momentum.

The Washington-based bank forecasts the global economy to grow 2.8 percent this year, down from its January estimate of 3.2 percent, according to its twice-yearly Global Economic Prospects report.

"Developing countries are headed for a year of disappointing growth, as first quarter weakness in 2014 has delayed an expected pick-up in economic activity," the report noted.

Bad weather in the United States, the crisis in Ukraine, rebalancing in China and political strife in several middle-income economies slow progress on structural reform, it said.

The bank has lowered its forecasts for developing countries to a growth of 4.8 percent this year, down from its January estimate of 5.3 percent, the third year in a row of below five percent growth for developing countries. Growth is forecast to pick up to 5.4 percent in 2015 and 5.5 percent in 2016.

China is expected to grow 7.6 percent this year, slightly down from its January estimate of 7.7 percent, but this will depend on the success of rebalancing efforts, the bank said. "If a hard landing occurs, the reverberations across Asia would be widely felt," it noted.

"Growth rates in the developing world remain far too modest to create the kind of jobs we need to improve the lives of the poorest 40 percent," said World Bank Group President Jim Yong Kim.

"Clearly, countries need to move faster and invest more in domestic structural reforms to get broad-based economic growth to levels needed to end extreme poverty in our generation," he said.

Despite first quarter weakness in the United States, the recovery in high-income countries is gaining momentum, the bank said, estimating that these economies will grow 1.9 percent in 2014, and will accelerate to 2.4 percent in 2015 and 2.5 percent in 2016.

The Euro area is on target to grow by 1.1 percent this year, while the United States economy, which contracted in the first quarter due to severe weather, is expected to grow by 2.1 percent this year, down from the previous forecast of 2.8 percent.

"High-income economies will contribute about half of global growth in 2015 and 2016, compared with less than 40 percent in 2013," the report said.

Short-term financial risks have become less pressing, in part because earlier downside risks have been realized without generating large upheavals and because economic adjustments over the past year have reduced vulnerabilities.

In the meantime, speculation over the timing and magnitude of future shifts in high-income macro policy may result in further volatility in countries like Brazil, South Africa and Turkey which are plagued by high inflation and current account deficits.

The bank said fiscal policy needs to tighten in countries where deficits remain large, including Ghana, India, Kenya, Malaysia, and South Africa. In addition, the structural reform agenda in many developing countries, which has stalled in recent years, needs to be reinvigorated in order to sustain rapid income growth.