The World Bank forecast that global gross domestic product will inch up 2.4 percent this year, from 2.3 percent in 2012. In its last forecast in June, the bank projected global growth would reach 3.0 percent in 2013.

Andrew Burns, lead author of the bank's Global Economic Prospects report, said that a recovery the bank had anticipated last year was now expected "closer to the end of the first quarter and into the second quarter of 2013, rather than beginning a little earlier."

The Bank warned that a drawn-out political battle in the United States over raising the government's borrowing limit and spending cuts could hit growth, spark a loss of confidence in the U.S. dollar and unnerve financial markets.

The World Bank also cut its forecast for developing countries, which last year grew at their slowest pace in a decade, to 5.5 percent in 2013 from 5.9 percent in the June forecast. It said growth in these countries should slowly pick up, reaching 5.7 percent next year and 5.8 percent in 2015.

Before the global financial crisis hit in 2007, developing countries as a whole were chalking up growth rates of around 7.5 percent, with China growing at an annual rate of 10 percent.

The World Bank forecast that Chinese growth would reach 8.4 percent this year, slowing to 7.9 percent by 2015.

In comparison, growth in advanced economies should reach a very weak 1.3 percent this year, weighed down by spending cuts, high unemployment and weak consumer and business confidence, the World Bank said. Activity should strengthen next year to 2 percent and 2.3 percent in 2015.

While financial markets were buoyed by measures adopted last year to address the euro-zone debt crisis, the World Bank urged Washington to outline a credible medium-term fiscal plan that "avoids episodes of brinkmanship" over raising the country's self-imposed debt ceiling.

The White House and the U.S. Congress did agree at the beginning of January to extend tax cuts for American families earning less than $450,000 a year as part of a deal over the so-called fiscal cliff. But lawmakers must still navigate the debt limit as well as thrash out a deal over drastic automatic sending cuts that were postponed until March 1.

"Policy uncertainty (in the United States) has already dampened growth," the World Bank said. "Should policymakers fail to agree such measures, a loss of confidence in the currency and an overall increase in market tensions could reduce U.S. and global growth by 2.3 and 1.4 percent respectively."

Burns urged developing countries to "maintain a steady hand on monetary policy" and not to react too forcefully to changes in developed countries. He said developing nations should focus on structural polices and investments to support sustained growth.

The Bank said most developing countries were operating at or near "full capacity" and additional efforts to boost output risk hitting inflation speed bumps.

Meanwhile, the World Bank said a decline in China's unusually high investment rate was not likely to affect global growth over the medium to long term, but warned that a sharp decline could have domestic and global consequences.

World Bank economic simulations suggest that a 10 percentage point deceleration in Chinese investment would cause Chinese GDP growth to slow by about 3 percentage points.

The Bank said a bitter territorial row between China and Japan over islands in the East China Sea has had an impact on Japanese exports to China.