Ultimate weapon / Chris Ryan.

Enhanced descriptions from Syndetics:

Three people. Three stories. And a desperate race for survival in a country caught up in the hell of war.

Nick Scott fought in the SAS -- the elite Special Forces unit of the British Army -- during the first Gulf War. Captured and tortured, he was left a broken man. His daughter Sarah is a beautiful young scientist at Cambridge University who appears to have cracked one of the great scientific secrets of our age: cold fusion. Now, she has vanished. Sarah's longtime on-and-off boyfriend, Jed Bradley, is one of the SAS's toughest young soldiers. Nick and Jed have never gotten along because Nick doesn't want his daughter dating a soldier. Deep down, Jed reckons he joined the SAS just to win Nick's approval.

Reluctantly, the two men combine their efforts to rescue Sarah and soon they are caught up in a global power play, a deadly web of intrigue in which Nick and Jed encounter a traitorous scientist willing to sell out his country; a sinister Arab intent on destroying Western civilization; and a beautiful but manipulative intelligence agent whose motives are unclear.

Nick and Jed must fight their way through a war-ravaged Iraq as the regime of Saddam Hussein collapses around them. It is a heart-stopping desperate race to find the woman they both love, and to unlock the secret of the Ultimate Weapon.