Email messages sent by White House aides using Republican National Committee (RNC) addresses have been "extensively destroyed," according to a congressional report.

According to the report released by the House Committee on Oversight and Government Reform on Monday, of the 88 White House officials using RNC accounts, the RNC has deleted records for 51 users.

The Bush administration originally said only "a handful" of such accounts existed, and later said the number was "50 over the course of the administration."

The report also found heavy use of the RNC account by some high-ranking officials.

For instance, it found about 140,000 messages sent to or received by Karl Rove, President George W. Bush's political advisor.

Responding to the report, White House spokesman Tony Snow dismissed the idea that the e-mails were intentionally destroyed, but did concede that the 140,000 e-mails Rove's RNC account was "a lot of emails."

According to U.S. laws, using campaign accounts like RNC accounts for official White House business and destroying administration records are violations of the Hatch Act and Presidential Records Act.

The House Committee on Oversight and Government Reform is investigating whether RNC email addresses were used for official work to avoid a record required by official email addresses and to what extent those acts violate the law.