Six months before the head of Al Qaeda in Iraq was killed by a U.S. airstrike, Abu Musab al-Zarqawi received a letter said to be sent by a top Al Qaeda official who said he was not happy with him and warned that he would be removed if he did not consult with the terror group's leadership on major issues.

Sent by an Al Qaeda leader named "Atiyah," who said he was in the northwest Pakistani region of Waziristan, the 11-page letter also praised al-Zarqawi, saying "you have hurt America, the largest infidel Crusader forces in history."

The letter provides a glimpse into the weakened leadership of Al Qaeda in Waziristan and shows the rift between the terror group and the leader of its Iraqi branch.

Two U.S. government officials, who spoke on condition of anonymity because of the sensitivity of the information, said the letter is believed to be authentic. They said Atiyah is considered to be Usama bin Laden's emissary to Iraq and served as a link between the Al Qaeda leader and al-Zarqawi.

It wasn't clear when Atiyah took over that role or precisely how close to bin Laden he is.

The Iraqi government identified Atiyah as an Algerian and in the letter he tells al-Zarqawi how he fought with militants in Algeria in the 1990s.

One of the U.S. officials said the 37-year-old, whose full name is Atiyah Abd al-Rahman, was born in Libya.The official said he is a religious scholar with knowledge of the Koran and Islamic law, and a veteran of the anti-Soviet jihad in Afghanistan. He joined Al Qaeda in the early 1990s, when it was first formed.

Atiyah is believed to be an explosives expert, the official said.

First revealed by Iraq's National Security Adviser Mouwafak al-Rubaie on Sept. 18, The Washington Post reported in Monday's editions that the letter was the first document to emerge from what the U.S. military described as a "treasure trove" of information uncovered from Iraqi safe houses at the time of al-Zarqawi's death.

The letter is dated the 10th of the Muslim month of Zhul Qadah, which was around mid-December last year and about six months before the Jordian-born al-Zarqawi was killed in a U.S. airstrike north of Baghdad.

In a warning to al-Zarqawi that he could be removed, the letter said that "anyone who commits tyranny and aggression upon the people and causes corruption within the land and drives people away from us and our faith and our jihad and from the religion and the message that we carry, then he must be taken to task."

"We must direct him to what is right, just, and for the best. Otherwise, we would have to push him aside and keep him away from the sphere of influence and replace him and so forth," Atiyah wrote.

Atiyah tells al-Zarqawi that on major issues he should consult with "your leadership, Sheik Osama (bin Laden) and the doctor (Ayman al-Zawahri) and their brothers ... as well as your Mujahedeen brothers in Iraq."

Among the issues that Atiyah cautioned al-Zarqawi against was the war he declared against Shiite Muslims and attacks the Iraqi branch had carried out in neighboring countries — an apparent reference to last year's triple suicide attacks in hotels in the Jordanian capital of Amman that killed dozens.

Al-Zarqawi also was asked in the letter to correspond with Al Qaeda in Waziristan through reliable messengers and was told not to attack Sunni clerics whether in Iraq or abroad in an apparent reference to the Sunni clerics who were assassinated after calling Iraqis to take part in last year's general elections.

"The war is long and our road is long. What is important is to keep the good reputation of yourself, the mujahedeen and especially your group," Atiyah wrote.