The deputy leader of al-Qaeda, Ayman al-Zawahiri, has appeared in a new videotape shown by Arabic satellite television station al-Jazeera.
Zawahiri tapes appear periodically. This one is from June 2005.
In the tape, he claims that US hints of a future reduction of troops in Iraq are "a victory for Islam".
And he calls on US President George W Bush to admit defeat in Iraq and Afghanistan and says he will soon be defeated in Palestine.
Al-Jazeera says the videotape dates from December.
The Egyptian-born former eye surgeon wears a white turban and a grey robe with an automatic rifle positioned behind him, in a pose typical of past videotaped recordings.
"I congratulate the Muslims on Islam's victory in Iraq. I said more than a year ago that the Americans' departure from Iraq is only a matter of time," he says.
"Bush, you must admit that you have been defeated in Iraq and that you are being defeated in Afghanistan and that you will soon be defeated in Palestine, with the help and strength of God," he also says.
Mr Bush said on Wednesday that the US would aim to put more Iraqi territory under the control of Iraqi security forces during 2006.
He added that if Iraqis made good progress, "we can discuss further possible adjustments" in US troop levels, although he refused to outline a timetable for withdrawal.
However, Zawahiri is likely to have made the tape before Mr Bush gave his comments. Al-Jazeera says the video carried the date of the Muslim lunar month which ended in December.
Zawahiri is regarded as Osama Bin Laden's right-hand man. The two have evaded capture since US-led forces brought down the Taleban regime in Afghanistan in 2001 following the 9/11 attacks on the US.