The White House revealed this week that Rove and 21 other White House officials have for years kept email accounts through the Republican party (RNC) to conduct political business without violating an act which forbids government employees from using government property like hand-held computer devices for partisan activities.
The White House disclosed on Friday that the Republican National Committee in early 2006 took away Rove's ability to delete emails sent and received through a party email account.
The White House has acknowledged that Rove and others at times conducted official business on RNC accounts and that some of the email traffic may have been deleted, including some related to the firing of the US prosecutors.
Dana Perino, the White House spokeswoman, had no explanation for why the RNC, the governing arm of the political party of George Bush, the president, would stop Rove from deleting emails.
Robert Luskin, Rove's lawyer, said Rove never intentionally deleted emails from any email accounts.
Luskin said: "Karl always thought that all of his emails were archived, no matter which account he used. Consequently he never used a political email account to avoid creating a record."
He added that Rove never tried to get his emails deleted and "was unaware until very, very recently that there was any deletion of RNC emails for any period".
Henry Waxman, California Democratic representative and chairman of the House of Representatives' government oversight committee, has said he is concerned White House officials might have violated the Presidential Records Act.
The incident is another complication for George Bush, the US president, who is under pressure from Democrats and some Republicans to get rid of Alberto Gonzales, the attorney-general, over the firing of the US prosecutors.
In advance of Gonzales' congressional testimony next week, the justice department released a new batch of documents about the firings.
An email written by Kyle Sampson, Gonzales' former chief of staff, and dated January 9, 2006, to Harriet Miers, the White House counsel at the time, listed some possible replacement prosecutors to those later fired.
Sampson had told congress last month he personally did not have any replacements in mind at the time they were fired.
Senator Charles Schumer, a New York Democrat, said the justice department still has many questions to answer.