US veterans of Iraq war shocked and bitter at its catastrophic turn

Colonel Samuel Whitehurst had been consumed with work in the last days of his brigade's nine-month stint in eastern Afghanistan when alarming news about his former battleground in northern Iraq began to reach him.

Whitehurst fired off an e-mail to the mayor of the Iraqi city of Samarra, who had become a close friend, saying he was thinking of him.

Days after a band of Islamic militants took over Mosul and several towns in the north in early June, he got terrible news: Colonel Gayath Sami, the Iraqi officer Whitehurst had groomed to run Samarra's security command centre, had been slain in the fighting.

"To find out that he had been killed," said Whitehurst, who commands the 3rd Brigade Combat Team of the 10th Mountain Division, deployed in Paktia province. "Those are the things I worry about - the friends I met there and what's going to happen to them."

The catastrophic turn Iraq has taken in recent weeks has startled US veterans who spent years seeking to set up the country, and particularly its security forces, for success. The Iraq war killed nearly 4,500 US troops and, by some estimates, cost taxpayers more than US$2 trillion.

The country's violent downward spiral as Islamist militants seized large swathes of territory has been particularly unsettling to those who are currently in Afghanistan at the tail end of America's longest war and hoping for a better outcome.