U.S., Russia, China, Israel snub cluster bomb ban

Some 111 countries were due to adopt the Convention on Cluster Munitions at an all-day signing ceremony in Oslo, Norway.

But four of the biggest cluster bomb makers -- Russia, China, Israel and the United States, which claims the devices are a vital part of its defense strategy, stayed away.

Cluster Munition Coalition activists behind the agreement expressed disappointment at the absence of the big four, but insisted it wouldn't undermine the treaty as it passes into international law.

"Obviously it's very disappointing that those countries aren't here, but at the same time, the strong message that this treaty sends will make it very clear to those countries that these are unacceptable weapons and inappropriate in future conflicts," CMC Co-Chair Richard Moyes told CNN from Oslo.