TIKRIT, Iraq — The stack of cash sat enticingly on the table beneath a beaded chandelier inside one of Saddam Hussein’s marbled palaces: $15,000 in red-and-green Iraqi notes.

Three tribal leaders inched closer as an American military commander explained how the bundle was theirs if they secured a 30-mile road through a lawless stretch of countryside.

Hoping to replicate a drop in violence in Anbar province, the American military has signed more than $5.2 million in contracts with local sheiks to protect roads and other infrastructure in Saddam’s home province of Salahuddin. That cash has bought the loyalty of more than 2,700 men in a region where support for the executed dictator runs deep.

American commanders say the strategy is yielding dividends: In the first 90 days, the number of bombs that exploded or were found in the areas secured by the tribesmen dropped up to 60% in some places.

But the aggressiveness with which such deals are being pursued here and in other Sunni parts of the country has stoked tension with the Shiite-led national government in Baghdad, which fears Sunni tribesmen will turn their guns on it once they have defeated their common enemy: Al Qaeda in Iraq.

If the Iraqi government does not pick up what are short-term arrangements between the Americans and the tribes, the consequences could be explosive.

“We have got 2,700 military-aged males that right now have a job and probably have some pride, and the rug is going to get ripped out from under them,” Lieutenant Colonel Mark Edmonds of the Army said. Colonel Edmonds is the deputy commander of the 3rd Brigade Combat Team, 82nd Airborne Division, which recently wrapped up 15 months in Salahuddin. “If I am an insurgent leader, I’m going to capitalize on that.”

Even among Sunnis in the province, many are suspicious of the paid alliances with America, which they say have caused disputes within families, emboldened local strongmen, and triggered a backlash by the most extreme elements of the insurgency. Attacks picked up again during the Muslim holy month of Ramadan, which in recent years has been a time of increased insurgent violence, and many of the bombings and shootings targeted the Americans’ new tribal allies. Before the tribes began working with the Americans, “Salahuddin was respected and there was security,” one of many leaders of the powerful Dulaimi tribe, Sheik Faisel Deham Draa, said. “Since it was established, it has spread chaos.”

He maintained that the Iraqi police and military were capable of maintaining security without the help of American-backed tribal fighters he dismissed as a “militia.”

American commanders concede that Tikrit, with its educated, largely secular population, has never been fertile ground for Islamic extremist groups such as Al Qaeda in Iraq. The dominant influence here is Saddam’s Baath Party, which is ideologically opposed to religious fundamentalism.

But the commanders say violence surged this year around the refinery towns of Baiji and Samarra, where the bombing of a revered Shiite Muslim shrine in 2006 pushed parts of Iraq into a sectarian war. They blame the arrival of increased numbers of insurgents fleeing the American troop buildup in Baghdad, Anbar, and Diyala provinces.