(CNN) -- Al Qaeda leader Osama bin Laden called Israel's recent offensive in Gaza a "holocaust," according to a purported message from him posted on an Islamist Web site.
Osama bin Laden, in an undated photo, apparently taped a message calling Israel's Gaza offensive a holocaust.
"The holocaust of Gaza in the midst of this long siege is an important and historic event and an articulate tragedy which affirms the need for detachment of the Muslims from the hypocrites. It is not right that our condition after what happened in Gaza be like our condition prior to it," the message said.
Al Qaeda says it wants to liberate the mosque from Israeli control.
The message -- an audiotape played over a still image -- is called "Practical Steps to Liberate Palestine" and it is dated March 2009, according to terrorism analyst Laura Mansfield.
The more than 33 minutes-long tape includes English subtitles, and English and Arabic transcripts were released by As Sahab, al Qaeda's media production center, Mansfield said.
The authenticity of the tape could not be verified.
The message says it's "clear" some Arab leaders have "conspired" with what it calls the "Zionist-crusader alliance" against the Palestinians in Gaza.
"They are the ones that America describes as the moderate leaders in our world," the message says.
The speaker urged Muslims to help insurgents "liberate" Iraq.
"For those honest in their desire to deliver al-Aqsa mosque, they should back the Mujahideen in Iraq with everything they need in order to liberate Mesopotamia," the message said, alluding to the Jerusalem mosque regarded as the third holiest place in Islam. "And with that they will have defeated the Zionists' biggest ally," referring to the United States.
Then, the fighters should move on to Jordan to "liberate all of Palestine from the sea to the river" from Israel.
When talking about Palestine, the speaker is referring to the region between the Mediterranean Sea and the Jordan River that includes the Jewish state of Israel and the Palestinian lands of the West Bank and Gaza.
In his last purported audio message in January, bin Laden called for a jihad, or holy war, to stop Israel's military campaign in Gaza.