DUBLIN, Ireland — Chief negotiators of a landmark treaty banning cluster bombs are predicting that the United States will never again use the weapons, a critical component of American air and artillery power.

The treaty formally adopted Friday by 111 nations, including many of America's major NATO partners, would outlaw all current designs of cluster munitions and require destruction of stockpiles within eight years. It also opens the possibility that European allies could order U.S. bases located in their countries to remove cluster bombs from their stocks.

The United States and other leading cluster bomb makers — Russia, China, Israel, India and Pakistan — boycotted the talks, emphasized they would not sign the treaty and publicly shrugged off its value. All defended the overriding military value of cluster bombs, which carpet a battlefield with dozens to hundreds of explosions.

But treaty backers — who long have sought a ban because cluster bombs leave behind "duds" that later maim or kill civilians — insisted they had made it too politically painful for any country to use the weapons again.

The treaty contains promises to mobilize international aid to cluster bomb-scarred lands such as southern Lebanon, where a 2006 war between the militant group Hezbollah and Israel left behind an estimated 1 million unexploded "bomblets."

In Washington, State Department spokesman Tom Casey said the treaty would not change U.S. policy and cluster munitions remain "absolutely critical and essential" to U.S. military operations.

He said U.S. officials in the State and Defense departments were studying whether the treaty would eventually oblige American bases in Europe to withdraw cluster munitions.

Ivan Oelrich, vice president for strategic security programs at the Federation of American Scientists in Washington, said he expected U.S. forces to keep using shells, rockets and bombs that break apart into smaller explosive objects because they have 10 times or more killing power than traditional munitions, particularly against troops in exposed terrain or in foxholes.

U.S. defense analysts said the majority of U.S. artillery shells are of the cluster variety.