The International Committee of the Red Cross (ICRC) confirmed on Friday (October 13) it had visited for the first time 14 suspected militants transferred from secret CIA-run jails to the Guantanamo Bay prison. The Swiss-based humanitarian body said that in all, it had seen 454 detainees from some 40 countries during its latest three-week visit to the U.S. detention facility in Cuba, which ends later on Friday (October 13). "During this visit we saw 454 detainees, including the 14 previously held by the CIA and recently transferred," ICRC spokesman Vincent Lusser said. The 14 include the suspected mastermind of the Sept. 11 suicide plane attacks, Khalid Sheikh Mohammed, and two other al Qaeda leaders, Ramzi Binalshibh and Abu Zubaydah. The Pentagon, which said on Thursday (October 12) that the ICRC had been granted access for the first time to the 14, has described them as "some of the world's most dangerous and vicious individuals". "The key thing is we were able to register them, which means that once they are in our system we are going to follow up on them all the time of their detention," Lusser said. All the detainees had had the opportunity to send Red Cross messages to their families, he said. In exchange for access to detainees world-wide, the ICRC keeps its findings confidential, sharing them only with detaining authorities. United Nations human rights bodies have called for the closure of Guantanamo -- where detainees have been held indefinitely without charge -- as well as of secret prisons where they say inmates are vulnerable to mistreatment. U.S. officials said last month the CIA had held fewer than 100 suspects in secret detention and that after the transfer of the 14, it held none.