UNITED NATIONS (AP) -- Member states failed to reach agreement Friday on a new U.N. treaty to regulate the multibillion dollar global arms trade, and some diplomats and supporters blamed the United States for triggering the unraveling of the monthlong negotiating conference.

Hopes had been raised that agreement could be reached on a revised treaty text that closed some major loopholes by Friday's deadline for action. But the U.S. announced Friday morning that it needed more time to consider the proposed treaty _ and Russia and China then also asked for more time.

"This was stunning cowardice by the Obama administration, which at the last minute did an about-face and scuttled progress toward a global arms treaty, just as it reached the finish line," said Suzanne Nossel, executive director of Amnesty International USA. "It's a staggering abdication of leadership by the world's largest exporter of conventional weapons to pull the plug on the talks just as they were nearing an historic breakthrough."

A Western diplomat, speaking on condition of anonymity because of the sensitivity of the issue, also blamed the U.S., saying "they derailed the process," adding that nothing will happen to revive negotiations until after the U.S. presidential election in November.

Chief U.S. negotiator Thomas Countryman refused to talk to several dozen reporters when the meeting broke up.

U.S. State Department spokeswoman Victoria Nuland, said in a statement Friday evening that the U.S. supports a second round of negotiations next year.

"While we sought to conclude the month's negotiations with a treaty, more time is a reasonable request for such a complex and critical issue," the satement said.

The draft treaty would require all countries to establish national regulations to control the transfer of conventional arms and to regulate arms brokers. It would prohibit states that ratify the treaty from transferring conventional weapons if they would violate arms embargoes or if they would promote acts of genocide, crimes against humanity or war crimes.

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, organized crime or for corrupt practices.

Many countries, including the U.S., control arms exports but 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 U.N. General Assembly voted in December 2006 to work toward a treaty regulating the growing arms trade, with the U.S. casting a "no" vote. In October 2009, the Obama administration reversed the Bush administration's position and supported an assembly resolution to hold four preparatory meetings and a four-week U.N. conference in 2012 to draft an arms trade treaty.

The United States insisted that a treaty had to be approved by the consensus of all 193 U.N. member states.

Ambassador Roberto Garcia Moritan, the conference chairman, said treaty supporters knew "this was going to be difficult to achieve."

He said negotiations failed because some delegations didn't like the draft though "the overwhelming majority in the room did." He added that some countries from the beginning of negotiations had "different views" on a treaty, including Syria, Iran and North Korea.

Amnesty's Nossel accused the U.S. of raising eleventh-hour issues "and wanting more time to consult with itself," which stopped the momentum toward agreement.

Despite the failure to reach agreement, Moritan predicted that "we certainly are going to have a treaty in 2012."

He said there are several options for moving forward in the General Assembly which will be considered over the summer, before the world body's new session begins in September.

Ambassador Jean-Hugues Simon-Michel, who led the French delegation, called Friday's result "the worst-case scenario."

"I'm disappointed but not discouraged," he said. "The ball is now in the court of the General Assembly but the risk is that countries may want to start negotiations from scratch."

Daryl Kimball, executive director of the Arms Control Association, said the General Assembly needs to decide whether to move forward with the treaty text that was close to adoption or reopen old issues.

"What we have now is an uncertain outcome that leaves in doubt the support of the major arms exporters and importers, including the U.S. and Russia, and that needs to be overcome," he said. "This is a delicate moment and it's going to require real leadership on the part of key states including the European countries, Washington and others."

The powerful National Rifle Association in the U.S. has portrayed the treaty as a surrender of gun ownership rights enshrined in the U.S. Constitution. The politically controversial issue has re-emerged since last week's shooting at a Colorado cinema that killed 12 people.

But the draft treaty reaffirms "the sovereign right and responsibility of any state to regulate and control transfers of conventional arms that take place exclusively within its territory, pursuant to its own legal or constitutional systems." And it states clearly that the treaty's aim is to establish the highest standards "for regulating, or improving the regulation of the international trade in conventional arms" _ not domestic trade.

On Thursday, a bipartisan group of 51 senators threatened to oppose the treaty if it falls short in protecting Americans' constitutional right to bear arms. In a letter to President Barack Obama and Secretary of State Hillary Rodham Clinton, the senators expressed serious concerns with the draft treaty that has circulated at the United Nations, saying that it signals an expansion of gun control that would be unacceptable.

During negotiations, the United States objected to any requirement to report on exports of ammunition, and that remains out of the latest draft. It does call for every country to regulate the export of ammunition.

Britain has taken the lead in pushing for a treaty.

Ahead of Friday's meeting, Britain's Deputy Prime Minister Nick Clegg discussed treaty prospects with U.N. Secretary-General Ban Ki-moon in London and both urged the treaty's adoption.

"Global rules govern the sale of everything from bananas to endangered species to weapons of mass destruction, but not guns or grenades," Clegg said. "This anomaly causes untold suffering in conflicts around the world. 1,000 people are killed daily by small arms wielded by terrorists, insurgents and criminal gangs."

The secretary-general said he was disappointed at the failure to agree on a treaty, calling it "a setback." But Ban said he was encouraged that states have agreed to continue pursuing a treaty and pledged his "robust" support.

At the end of the negotiating session, Mexico read a joint statement from more than 90 countries saying they "are determined to secure an Arms Trade Treaty as soon as possible."