PARIS (AP) — The Organization for Economic Cooperation and Development is warning of a "marked slowdown" in eurozone economies next year and says the European Union needs to clarify its anti-crisis measures.

In an update Monday of economic forecasts timed to coincide with this week's meeting of the Group of 20 major economies, the OECD says "patches of mild negative growth" are likely in the eurozone in 2012.

It says economic growth in the eurozone will stall at 0.3 percent next year, after just 1.6 percent growth this year.

The Paris-based OECD says "detailed information is needed" on how the EU will implement the package of measures announced last week aimed at resolving the European debt crisis, to prevent a repeat of the global crisis that hammered economies three years ago.