A very curious letter, if it proves to be authentic.
In the missive, Zawahiri apparently warns tactics such as the killing of hostages and bombings of mosques may alienate the “Muslim masses,” Mr Whitman said.
“In this letter, he talks about believing that the eventual governance of Iraq must include the Muslim masses, and that they are at risk of alienating those,” he told reporters.
The letter was also said to detail the strategy of Muslim extremists to create an Islamic state centred on Iraq that could expand into neighbouring countries.
Zawahiri included a plea for financial support, Reuters news agency quoted Mr Whitman as saying.
The New York Times quoted a senior official as saying that the 6,000-word letter was dated early in July, and was obtained by US forces involved in counterterrorism operations in Iraq.
The letter also noted that they were losing in Afghanistan and they had lost many of their key leaders. Zawahiri is also badly in need of money apparently.