Um Saad, a middle-aged woman living in the Sunni district of Khadra in west Baghdad, blames the Americans for the death of her husband and two of her sons and threatens revenge.

"They are monsters and devils wearing human clothes," she exclaims vehemently. "One day I will put on an explosive belt under my clothes and then blow myself up among the Americans. I will get revenge against them for my husband and sons and I will go to paradise."

Just as the White House and the Pentagon were trumpeting the success of "the surge" – the dispatch of extra American troops to Iraq last year – and the wire services' claim that the country has enjoyed "months of relative calm", Um Saad saw Saif, her second son, shot dead as he opened the door of her house.

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Iraq is still convulsed by violence and security has only improved compared to the height of the sectarian civil war in 2006 and early 2007 when 65 Iraqis were being killed every day. By this February the number of dead had fallen to 26 a day though this has risen to 39 in March so far.

The misery of people like Um Saad is the cumulative result of years of war. Dressed in dark robes, sitting in the bare sitting room of her modest house in al-Khadra, this 49-year-old woman tells how her family was slowly destroyed. "I am not educated and I only went to primary school," she says. "I married an air force pilot called Latif and we had three sons and one daughter."

Latif was stationed at Bakr airforce base at Balad, north of Baghdad, during the 1990-91 Gulf War and was killed in an American bombing attack. "I didn't get support from our uncles and aunts so we lived on his pension and we sold a car, a Chevrolet Malibu, he had been given by the government because he was a pilot," says Um Saad.

Her eldest son, Saad, wanted to enter the military academy just like his father. Um Saad said she did not want to lose him and instead he went to the police academy and had graduated as a police lieutenant when Saddam Hussein was overthrown in April 2003. She wanted him to resign. "After the fall of Iraq the police were the second target [of Sunni guerrillas] after the Americans."

Saad equivocated over resigning since he held the Americans responsible for killing his father, but the family needed his salary. He finally decided to leave the police, but before he could do so, on 25 October 2003, his police station at Khadra was hit by a large car bomb. He was uninjured by the blast but, as he ran with his pistol drawn to help a friend, American soldiers at the scene thought he was attacking them. "They shot him dead with six bullets in the head and many more in the body," says his mother.

Um Saad says it was at this point she began to hate the Americans: "I do not look on them as human beings." Her priority was to try to save her three surviving children. She was particularly worried about Saif, 17 and in his fifth year in secondary school, because many of his friends had joined al-Qa'ida in Iraq. Um Saad thought it would be safest if Saif went to Syria and she enticed him to go there at the end of 2006 by telling him that his cousin Mariam, whose family had already fled there, was in love with him and wanted to marry him. Saif came back to Baghdad in October last year when Syria changed its visa and residency requirements.

Um Saad was "desperately worried because the security situation was bad". It was at this time that the US forces in Khadra had set up al-Sahwa, the Awakening Council, as a Sunni anti-al-Qa'ida force.

"I was so stupid," says Um Saad bitterly. "I thought the danger was that Saif would join al-Qa'ida because the Americans had killed his father and brother." In fact he secretly joined al-Sahwa and was expecting to earn $400 a month. On the night of 15 February as the family were having their supper there was knock on the door. Saif answered it and Um Saad heard shots. "I was too late," she says. "He was lying dead on the doorstep and on his chest was a piece of paper saying: 'Death to al-Sahwa and all enemies of al-Qa'ida'."