The IMF published its 249-page World Economic Outlook, saying the U.S. economy "remains at the center of events."
The U.S. government is in a partial shutdown because of political budgetary disputes, including disagreement about whether to raise the debt ceiling before an Oct. 17 deadline. The IMF, however, said emerging economies are facing troubles of their own.
For Nigeria, the IMF said it expected gross domestic product to grow 7.4 percent next year, a 1.2 percent increase from the 2012 forecast.
Nigeria in July imposed a state of emergency in parts of the Muslim north but eased restrictions during the holy month of Ramadan. At least 60 people were killed when Nigerian militant group Boko Haram attacked a mosque in the north in August.
A July report from the Nigeria Extractive Industries Transparency Initiative estimated the country lost $10.9 billion in oil revenue to theft and sabotage from 2009 to 2011.
Nevertheless, the IMF was upbeat about Nigeria's economic prospects.
"In Nigeria, still high oil prices underpinned strong growth, notwithstanding temporary downdrafts from security problems in the north and oil theft," it said.