Oslo, Norway ? Forty-six countries agreed Friday to push for a global treaty banning cluster bombs, a move activists hope will force the superpowers that oppose the effort – the U.S., China and Russia – to abandon the weapons.

Organizers said the declaration was needed despite the absence of key nations at a conference in the Norwegian capital to avoid a potential humanitarian disaster posed by unexploded cluster munitions.

Cluster bomblets are packed by the hundreds into artillery shells, bombs or missiles, which scatter them over vast areas, with some failing to explode immediately. The unexploded bomblets can then lie dormant for years after conflicts end until they are disturbed, often by children attracted by their small size and bright colors.

Of the 49 countries attending the Oslo conference, only three – Japan, Poland and Romania – rejected the declaration calling for a treaty by next year. Some key arms makers – including the U.S., Russia, Israel and China – snubbed the conference.

But even deeply skeptical nations like Canada, Britain and Germany, were swayed to join the Norwegian-led initiative in what activists hailed as a major step forward.

Jody Williams, an American who shared the 1997 Nobel Peace Prize for a global campaign to ban land mines, urged nations supporting a cluster bomb treaty to move ahead without the major powers.

“They should do it the same way, with countries that realize that there are 191 countries in the world, and not just three,” she told The Associated Press.

Last summer’s Israel-Hezbollah war helped bring cluster munitions to the forefront of the international agenda. The U.N. estimated that Israel dropped as many as

4 million bomblets in southern Lebanon during the conflict, with as many 40 percent failing to explode on impact.

Mark Regev, spokesman for Israel’s Foreign Ministry, said Israel did not use any munitions that were outlawed by international treaties or law. He said if the cluster bombs declaration evolves into a treaty, Israel would examine it and then decide how to respond.

Countries opposed to the Oslo conference say cluster bombs are being discussed under the U.N. Convention on Conventional Weapons.

In Washington, State Department spokesman Sean McCormack said the convention has produced a treaty the U.S. has signed and forwarded to the Senate for ratification. He did not provide details on what the treaty says about cluster bombs.

“We have taken very seriously the international discussion with respect to the threat posed by unexploded ordnance to innocent civilians,” McCormack said.

He said the U.S. has spent about $1 billion over the past decade to help clean up unexploded munitions in East Asia, Southeast Europe and the Middle East. He added, however, that cluster bombs “do have a place and a use in military inventories.”