The White House began mandatory, hourlong briefings Tuesday for an estimated 3,000 staffers on ethics and the handling of classified information in response to the indictment of a top official in the CIA leak investigation.
Among those who attended the first ethics briefing were some assistants to the president with top security clearances, White House spokesman Scott McClellan told reporters.
President Bush's top political adviser, Karl Rove, was not among the first group, although he was expected to attend an ethics class later this week.
The White House counsel's office will conduct presentations Tuesday, Wednesday and Thursday for those aides with security clearances.
Briefings for other aides in the White House and the executive office of the president will follow.
The ethics course comes after Vice President Dick Cheney's former chief of staff, Lewis "Scooter" Libby, was indicted on five counts of obstructing justice, perjury and lying in the two-year investigation into the leak of covert CIA operative Valerie Plame's identity.
If convicted, Libby, who resigned from his post in the White House, faces a maximum sentence of 30 years in prison. He has pleaded not guilty.
The five-count indictment against Libby maintains that other government officials were aware of, if not involved in, leaking the identity of Plame to the media.
One of those officials is Rove, who serves as Bush's deputy chief of staff.
Rove was not indicted along with Libby, but lawyers involved in the case said Rove remained under investigation and may still be charged in the case.
The briefings were scheduled for staffers according to the first letter of their last name.
If that practice is followed, Rove would be expected at a session at 4 p.m. on Wednesday.
"The president thought it was important to have these refresher briefings for all White House staff in light of recent circumstances," McClellan said. "It is mandatory."
In addition to government ethics, the briefings will cover rules for protecting classified information.
The ethics briefings come amid pressure from congressional Democrats to fire Rove or strip his security clearance.
Asked if Rove still had his security clearance, McClellan said: "Yes."
Plame's identity was leaked to the media in July 2003 after her diplomat husband, Joseph Wilson, accused the Bush administration of twisting intelligence on weapons of mass destruction to justify the war in Iraq.