DUBLIN, Ireland — Diplomats from more than 100 nations agreed on a treaty Wednesday to ban current types of cluster bombs and require the destruction of stockpiles within eight years.

However, the talks did not involve the biggest makers and users of cluster bombs: the United States, Russia, China, Israel, India and Pakistan. And the pact leaves the door open for new types that could pick targets more precisely and contain self-destruct technology.

Cluster munitions, fired by artillery or dropped from aircraft, scatter dozens or hundreds of "bomblets" across an area as big as two football fields to attack concentrations of troops and vehicles. Critics of the weapon complain that bomblets often fail to detonate on impact and instead explode when civilians later stumble on them.

The breakthrough on a ban capped more than a year of negotiations begun in Norway and pressed home over the past 10 days in Dublin. Nations are expected to sign the document in December in the Norwegian capital, Oslo.

Ireland and other lead sponsors plan to unveil the treaty Friday after it is translated into several languages.

A draft — obtained by The Associated Press as talks wound down with no major issues outstanding — declares that a signatory nation "undertakes never under any circumstances to use cluster munitions" nor "develop, produce, otherwise acquire, stockpile, retain or transfer to anyone, directly or indirectly, cluster munitions."

The agreement contains two key concessions sought by the U.S. government, which shunned the talks but nonetheless cast the biggest shadow over deliberations.

The pact would allow countries that sign the treaty to keep cooperating militarily with those that do not. Earlier drafts sought to prohibit such cooperation, but the U.S. and its NATO allies opposed that idea on the grounds it would complicate joint peacekeeping operations.

The treaty's detailed definition of what a cluster bomb is — and isn't — also will allow development of more advanced weapons.

It specifies that designs are permitted if each weapon contains fewer than 10 bomblets. Each bomblet would have to weigh more than 8.8 pounds, contain targeting technology designed to single out a target, and have built-in security measures that would defuse duds.

The self-destruct rule is meant to reduce the number of civilians killed or maimed by bomblets. Rights groups say tens of thousands of people have stumbled across unexploded bomblets and accidentally detonated them.

The treaty says any future cluster bomb must meet all of those requirements "to avoid indiscriminate area effects and the risks posed by unexploded submunitions."

Campaigners against the use of cluster bombs welcomed the treaty's commitment requiring signatories to fund projects that will clear up unexploded bomblets and support families and communities victimized by cluster munitions.

But they also expressed worries that the treaty concedes too many loopholes.

"We do feel some disappointment, because we have the feeling we missed the chance to make clear that (treaty supporters) should not assist other counties that are using cluster munitions," said Hildegarde Vansintjan, spokeswoman for Handicap International.

Her group, which was involved in the negotiations, has spent more than a decade helping people who have lost limbs, sight or other faculties in cluster-bomb explosions.

Before the treaty was announced, British Prime Minister Gordon Brown sought to give the talks a nudge by announcing that Britain will take all of its cluster weapons out of service.

"I look forward to other countries following us in this action," he said.

Britain's Ministry of Defense identified the two weapons systems to be taken out of service as the M-85, last used in Iraq in 2003, and the M-73, which has been deployed to Afghanistan but never used in combat. Both are artillery-fired weapons.