Pressed by federal prosecutor Robert Spencer, Moussaoui said there is "no remorse for justice," CNN reported.
When Spencer asked him if he would carry out attacks tomorrow, Moussaoui answered "today." Asked about testimony from the widow of a military officer killed at the Pentagon, Moussaoui answered, "Make my day."
Earlier, in his direct testimony, Moussaoui attacked his own lawyers.
"I felt you did not have my best interest at heart," Moussaoui told a court-appointed lawyer, Gerald Zerkin, who was questioning him. "First, you are an American. Second, you are Jewish."
Moussaoui, who has admitted being a member of al-Qaida and claims he was part of a team designated to attack the White House, faces either the death penalty or life in prison with no parole. In his testimony in the first phase of the trial, when his lawyers tried to present him as someone so unstable al-Qaida leaders distrusted him, Moussaoui sabotaged their case on the witness stand.
"Your idea to portray me as crazy was not going to work," Moussaoui told Zerkin on Thursday.
Moussaoui also complained of not having a Muslim lawyer.