Ratings agency Standard & Poor's said it had put European Union on the list for possible downgrade of its AAA credit rating.
The announcement comes shortly after the agency announced a similar action against 15 eurozone countries. The rating of six eurozone economies with the highest AAA rating - Austria, Finland, France, Germany, Luxembourg and The Netherlands - may be downgraded by one notch and by up to two notches for the other governments..
"The CreditWatch on the EU is an expression of our concerns about the potential impact on the future debt service capacity of eurozone sovereigns, and therefore also the EU, in the context of what we view as deepening political, financial, and monetary problems within the eurozone," S&P said in a statement.
The ratings agency said eurozone members account for 62 percent of the EU's 2011 budgeted revenues, including Germany and France, who make up 32 percent of union's 2011 budgeted revenues.
The agency said the ratings may be reviewed as early as this week, after the EU summit ends on Friday.
S&P said it may also downgrade ratings of Europe's leading banks, including Germany's Deutsche Bank and Commerzbank, France's BNP Paribas, Societe Generale, BPCE, Natixis, Credit Agricole, Italy's Intesa Sanpaolo and Unicredit and others.
The CreditWatch list means that there is 50 percent possibility that the ratings will be downgraded within 90 days.