The U.S. securities agency is accusing the China-based affiliates of some of the world's largest accounting companies of violating American financial laws by refusing to divulge information about their audit work for Chinese companies that are under investigation.

The Securities and Exchange Commission said Monday that five companies have “refused to cooperate” for several months. The agency made the accusations against Deloitte Touche Tohmatsu, Ernst & Young Hua Ming, KPMG Huazhen, PricewaterhouseCoopers Zhong Tian and BDO China Dahua.

The SEC said the five accounting firms have been withholding their work papers related to nine Chinese companies whose securities are traded on U.S. stock exchanges. The agency said it can only determine if the audits for the nine companies are accurate if they have access to the auditors' calculations.

The U.S. agency has been cracking down on illegalities involving the trading of foreign companies' stock. The SEC has revoked the registration of securities for nearly 50 companies, and has filed fraud cases against more than 40 companies and their executives.