The SEC is extremely concerned about foreign auditors.
In particular, the SEC is worried that those who work in certain European countries and in China are not subject to auditor requirements or the PCAOB. Essentially, the SEC is concerned over the lack of US oversight over these foreign auditors. Further, the SEC is concerned about if their audit reports provide accurate information for investors.
Although the SEC has not indicated enforcement action, it is considering if it should instruct the PCAOB to engage in further regulation of these entities and their issuers. See http://WWW.SEC.GOV/NEWS/SPEECH/120312LAA.HTM