The 193 members of the United Nations were on the verge of approving an unprecedented global arms trade treaty (ATT) on Thursday, as a first step towards regulating the $70-billion business across international borders.

Under the ATT, ratifying nations would accept international standards for conventional weapons sales that would be linked to protection of human rights, including preventing war crimes and protecting civilians. The treaty was to be considered for passage on Thursday afternoon.

While more than 120 countries have pressed for “robust” language in the ATT, Washington is said to be under pressure from its domestic gun lobby to protect the constitutional right to bear arms.

American negotiators have pushed back on any national regulation of arms and also rejected proposals to include ammunitions within the scope of the ATT.

Reports, however, suggest that the latest draft of the treaty would be acceptable to the U.S. While this text covers weapons such as tanks, armoured combat vehicles, large-calibre artillery systems, combat aircraft, attack helicopters, warships, missiles and missile launchers, and small and light arms, it does not explicitly cover predator drones and grenades.

While most nations were said to be on board with the draft text, a few — including India, Syria and Iran — were seen as nations that “could still cause trouble”, a European diplomat speaking on condition of anonymity told the Reuters news agency. That diplomat, however, noted that he would “wager the treaty will pass by consensus”.

India is among the largest importers of weapons in the world. Human rights groups have voiced concern about India, specifically complaining about a potential loophole in the current draft involving the exemption of certain weapons transfers relating to prior defence cooperation agreements — a feature that some delegates reportedly dubbed the “India clause” because it was something India allegedly pushed hard for.

Meanwhile the U.S. appeared ominously close to playing the same spoiler role that it did during 2012 treaty negotiations after Senate Republicans passed an amendment, by a 53-46 vote, against U.S. ratification of the treaty, purportedly to uphold the Second Amendment on rights to bear arms. The pro-gun NRA has also “vowed” to block the Senate’s ratification of the ATT.

However, experts argued that the Obama administration would probably support the ATT on this occasion.