The UN General Assembly on Tuesday passed the first treaty regulating the global conventional weapons trade in an attempt to bring transparency and protection of human rights to the often murky industry.

Only Syria, North Korea and Iran -- which had blocked the treaty last week -- voted against. However, two of the world's most prolific arms traders, Russia and China, and major weapons buyers Egypt and India, were among the 23 countries abstaining.

The first major arms accord since the 1996 Comprehensive Nuclear Test Ban Treaty covers the estimated $80-billion-a-year trade in tanks, armored combat vehicles, large-caliber artillery, combat aircraft, attack helicopters, warships, missiles and missile launchers, as well as small arms.

The treaty has no automatic enforcement. However, it seeks to push the weapons industry to take human rights into account.

Countries abiding by the treaty would establish national controls on arms exports. They'd also have to be sure that weapons being exported would not be used in genocide, war crimes, or by terrorists or organized crime.

"The world has been waiting a long time for this historic treaty," Brian Wood, head of arms control and human rights at Amnesty International, said.

The UN assembly voted by an overwhelming 154-3 margin for the resolution. Individual nations can start ratifying from June and once the 50th country ratifies -- a process that could last between one and two years -- the treaty takes effect.

The United States welcomed the vote, saying the UN treaty would help stem weapons shipments fueling war crimes. Secretary of State John Kerry called the measure "strong, effective and implementable."

In Britain, Prime Minister David Cameron called it a "landmark agreement that will save lives and ease the immense human suffering caused by armed conflict around the world."

The treaty will "reduce the number of illegal arms and make it harder for these to reach the hands of criminals and terrorists," he said.

However, Chinese ambassador Li Baodong said "China is not in favor of pushing a multilateral treaty through the General Assembly.... It is a negative precedent, we should negotiate by consensus."

And among those few casting no votes, North Korea's UN representative Ri Tong-Il called the treaty "unbalanced." He said it did nothing to curb exports, while failing to stop "the diversion to non-state actors, which is another source of profit for exporters."

There was criticism from the Conflict Awareness Project, a non-governmental research organization, which said the treaty left a huge loophole for the middlemen in arms dealing networks.

"Since the broker is the central actor using the cover of legitimate business to divert weapons into the illicit trade, of all actors, this is the one requiring the strictest regulation," CAP's executive director Kathi Lynn Austin said.

"States that are serious about impeding illicit arms trafficking and protecting the legitimate trade in arms should implement a mandatory licensing and registration regime for all arms brokers," she said. "Until then, these middlemen remain comfortably assured of conducting their lethal business as usual."

But there was especially strong support during 10 days of arduous negotiations at the United Nations from African and Latin American states that for decades have been among the prime markets for weapons exports.

The United States -- the world's biggest arms dealer, with 30 percent of the market -- was another big backer, although ratification by Congress is not assured.

Russia says it has not decided whether or not to ratify the text. It says there are "omissions" in the treaty and "doubtful" provisions, such as the failure to control arms transfers to non-state groups.

Russia said it is worried about weapons getting into the hands of Chechen rebels, although for two decades the main sources of new weaponry in the tiny Caucasian province have included corrupt Russian suppliers and even military personnel.