(CNN) Gina Haspel, President Donald Trump's embattled pick for CIA director, sent a letter Monday to Sen. Mark Warner, the top Democrat on the Senate Intelligence Committee, seeking to clarify her position on the agency's advanced interrogation program.

Haspel has come under fire for her role in the program and what some lawmakers, including Sen. John McCain , have viewed as an unsatisfactory denunciation of the use of torture. During her confirmation hearing, Haspel vowed that she would not restart the interrogation program as head of the CIA.