The measure ignited big rallies in financial stocks Friday that have been the target by sellers as the credit crisis worsened.

"The Commission is committed to using every weapon in its arsenal to combat market manipulation that threatens investors and capital markets," SEC Chairman Christopher Cox said in a statement.

"This action, which would not be necessary in a well-functioning market, is temporary in nature and part of the comprehensive set of steps being taken by the Federal Reserve, the Treasury, and the Congress," Cox said.

The SEC’s emergency order will be effective immediately and will terminate at 11:59 p.m. New York time on Oct. 2, 2008, the Commission said in a statement.

Cox has been under fire for not acting to control the practice that had led to sharp declines in U.S. and European financial stocks since the onset of the credit crunch.

The order may be extended beyond 10 days if the SEC deems an extension necessary in the public interest and for the protection of investors, but the order will not be extended for more than 30 calendar days in total duration, the agency said.