Iran, North Korea and Syria blocked adoption Thursday of a U.N. treaty that would regulate the multibillion-dollar international arms trade which required agreement by all 193 U.N. member states.

In an unexpected twist, Mexico proposed that the conference go ahead and adopt the treaty Thursday without the support of the three countries, saying there was no definition of “consensus.” Delegates then started debating whether this should be done and several countries supported Mexico, but the Russian delegation called the proposal “a manipulation of consensus” and objected.

Kenya said “the will of the overwhelming majority is clear” and when the meeting closes a letter will be sent to Secretary-General Ban Ki-moon with a draft resolution asking the U.N. chief to bring the treaty before the General Assembly for adoption as soon as possible.

Australian Ambassador Peter Woolcott, the meeting chair, suspended the meeting after Iran, North Korea and Syria raised their nameplates signifying their refusal to join consensus. Earlier, they gave speeches outlining their objections to the treaty.

Both Iran and North Korea are under U.N. arms embargoes over their nuclear programs, while the Syrian government is now in the third year of a civil war.

When Woolcott reconvened the meeting, all three countries reiterated that they would not join consensus.

Hopes of reaching agreement on what would be a landmark treaty were dashed last July when the U.S. said it needed more time to consider the proposed accord — a move quickly backed by Russia and China. In December, the U.N. General Assembly decided to hold a final conference and set Thursday as the deadline.

U.N. diplomats, speaking on condition of anonymity because negotiations have been private, said Wednesday the United States was virtually certain to go along with the latest text.

There has never been an international treaty regulating the estimated $60 billion global arms trade. For more than a decade, activists and some governments have been pushing for international rules to try to keep illicit weapons out of the hands of terrorists, insurgent fighters and organized crime.

The draft treaty would not control the domestic use of weapons in any country, but it would require all countries to establish national regulations to control the transfer of conventional arms, parts and components and to regulate arms brokers. It would prohibit states that ratify the treaty from transferring conventional weapons if they violate arms embargoes or if they promote acts of genocide, crimes against humanity or war crimes.

The final draft made this human rights provision even stronger, adding that the export of conventional arms should be prohibited if they could be used in attacks on civilians or civilian buildings such as schools and hospitals.

In considering whether to authorize the export of arms, the draft says a country must evaluate whether the weapon would be used to violate international human rights or humanitarian laws or be used by terrorists or organized crime. The final draft would allow countries to determine whether the weapons transfer would contribute to or undermine peace and security.