UNITED NATIONS — The U.N. General Assembly overwhelmingly approved the first international treaty regulating the global arms trade Tuesday, after a more than decade-long campaign to keep weapons from falling into the hands of terrorists and human rights violators.

Loud cheers erupted in the assembly chamber as the electronic board flashed the final vote: 154 in favor, 3 against and 23 abstentions.

“This is a victory for the world’s people,” U.N. Secretary-General Ban Ki-moon said. “The Arms Trade Treaty will make it more difficult for deadly weapons to be diverted into the illicit market.”

The United States, the world’s biggest arms exporter, voted yes.

Iran, North Korea and Syria — all facing arms embargoes — cast the only no votes. They argued, among other things, that the agreement favors major arms suppliers like the U.S. over importers that need weapons for self-defense.

Russia and China, which are also major arms exporters, abstained along with India and Indonesia, while nuclear-armed Pakistan voted in favor. Many Arab countries, including Egypt, Saudi Arabia, Sudan and Qatar, abstained.

Never before has there been a treaty regulating the global arms trade, which is estimated to be worth $60 billion today and which Amnesty International predicts will exceed $100 billion in the next four years.

What impact the treaty will actually have remains to be seen. It will take effect 90 days after 50 countries ratify it, and a lot will depend on which ones ratify and which ones don’t, and how stringently it is implemented.

As for its chances of being ratified by the U.S., the National Rifle Association has vehemently opposed it, and it is likely to face stiff resistance from conservatives in the Senate.