PITTSBURGH - European Commission President Jose Manuel Barroso expressed concern on Friday that the G20 countries were not moving fast enough to help achieve a United Nations agreement on fighting climate change.

We will only achieve a full and sustainable recovery if we also tackle climate change and kick-start trade. This is a test of credibility for the G20 -- failure is not an option, he said in a statement at the close of the leaders' summit.

I do not hide my concern at the slow rate of progress. Negotiations cannot be an open-ended process. It's time to get serious now, not later.

(Reporting by Jeff Mason and Darren Ennis; Editing by Leslie Adler)