BAGHDAD, Iraq (CNN) -- The U.S. military says a recent raid uncovered a detailed letter from an al Qaeda in Iraq militant to the group's leader about how the insurgent network should continue to generate economic chaos and "psychological conflict" and must bear down against American-backed Sunni militias.
An Iraqi mother and daughter are helped Tuesday after a car bombing in Baquba blamed on al Qaeda in Iraq.
Maj. Gen. Kevin Bergner told reporters at a news conference on Wednesday about a letter to Abu Ayyub al-Masri, the head of al Qaeda in Iraq, from a militant named Abu Safyan. The document was posted on the Multi-National Forces-Iraq Web site.
The sentiments reflect the tenacity of and continuing challenges posed by the predominantly Sunni militant network believed to be responsible for bombings that erupted across Iraq on Tuesday. Bergner said it "provides further evidence about the strategy and tactics of violence" the group is pursuing.
Bergner said a March 5 raid northwest of Baghdad resulted in three insurgents killed, including Abu Safyan, and three others captured. Troops seized a suicide vest, computer material and a stack of documents, including the document from Abu Safyan -- who was believed to be from Diyala province. Abu Safyan lays out a variety of tactics that militants should pursue.
"We must always leave the enemy in psychological conflict" so that "they can never have stability," according to the document. With such instability, they "will not all unite against us," it adds.
Bergner said that while authorities are investigating Tuesday's bombings in Baghdad, Ramadi, Mosul, and Baquba that killed 60 people and wounded more than 100 others, the strikes have the "hallmark" of being perpetuated by al Qaeda in Iraq.
The group has been considered the coalition's top foe in Iraq, even though troops have been distracted in recent weeks by fighting rogue Shiite militias.
Al Qaeda in Iraq has been described by military officials as having a largely foreign leadership but made up of Iraqis. It is distinct from al Qaeda in Afghanistan and Pakistan, but it is not clear how closely both the Iraqi and the South Asian al Qaeda groups cooperate.
The letter details the need for fostering "security chaos" among the anti-al Qaeda in Iraq and mostly Sunni awakening groups, Shiites and Kurds, the coalition forces, and the government.
"This will lead to weaken them, particularly the Maliki Shia government, by wisely, intelligently and cautiously spreading sedition among them," the letter said, referring to Prime Minister Nuri al-Maliki.
In the letter, Abu Safyan considers awakening groups a top threat to al Qaeda in Iraq and proposes a media campaign that would discredit the awakening forces by passing along false information about them.
The jihadi says al Qaeda in Iraq militants should consider infiltrating the government and security forces to foster trust. That atmosphere would enable militants to conduct attacks, including strikes against Shiites.
"We will work against them and attack them as they fight among themselves," Abu Safyan is quoted as saying.
Abu Safyan also calls for the disrupting the economy by attacking gas and oil fields, pipelines, tankers, electric stations and power lines. He suggests contaminating water lines and lakes.
Such sabotage would serve to "halt payment of the military and police salaries and the awakening movement associated with the occupier and Maliki's malignant government. Even the American Army will weaken since it depends on the Iraqi oil and gas wealth. The enemy will gradually drown step by step."
Abu Safyan talks about the need to "bring many brothers who have sharia knowledge and abide by the teachings of Islam from the outside of Iraq."
"They will explain to the people why we are fighting and whom we are fighting with, we must explain to them whom the mujahideen are and who are the people we're fighting."
The militant also called for good protection of communities under their control.
"We must dig trenches around the villages and cities to prevent the enemy from entering our areas," the document said.
Abu Safyan also called for organizing fighting groups by having an emir as commander with sniper, assassination and martyrs' groups.
It also cautions vigilance against allowing the "enemy" to infiltrate its apparatus and exhorts its fighters to keep silent about operations.
Sometimes, "they speak of our operations and area's secrets among their families and their wives in their houses, which unfortunately lead to the spread of our secrets." E-mail to a friend