(Updates headline, fixes typo in graf 2, new info grafs 5 & 6)

The International Monetary Fund is a little more optimistic about global economic growth as European nations have taken action to cope with their debt crisis, and the U.S. economy grew a little faster.

Speaking about the IMF's “World Economic Outlook” on Tuesday, research director Olivier Blanchard said the global economy has been on a “roller coaster” for the past six months, leaving an “uneasy calm.”

The International Monetary Fund's report comes as officials from the many member nations of the IMF and the World Bank gather in Washington for talks this week.

Blanchard said the world economy will expand by about 3.5 percent this year, and a little faster next year. The report says emerging markets will continue to grow faster than developed economies. For example, the United States' economy will expand 2.1 percent in 2012, Europe will shrink by three-tenths of a percent, while China will expand more than 8 percent.

The IMF also says the United States must come up with plans to cut debt over the medium term, but avoid slashing spending or raising taxes so quickly that it hurts the current recovery. The lender urges Europe to continue and expand efforts to boost its economy.

The global lender said Sub-Saharan Africa had another year of strong growth, and is one of the areas least affected by the recent financial turmoil.