A month-long review conference on the 1970 nuclear Non-Proliferation Treaty ended in failure on Friday after its members were unable to overcome disagreements on an atomic weapons ban for the Middle East.
After four weeks of negotiations at the United Nations on ways to improve compliance with the pact, there was no consensus among its 191 signatories. US Under Secretary of State Rose Gottemoeller announced there was "no agreement" and accused some countries of undermining the negotiations.
Gottemoeller did not specify any nations but diplomats said she was referring to Egypt.
"We have made clear throughout the process that we will not accept the efforts by some to cynically manipulate the (conference) or try to leverage the negotiation to advance their narrow objectives," she told attendees.
Egypt denied trying to wreck the conference.
The US concerns were echoed by Canada and Britain. Cairo's top delegate, Assistant Foreign Minister Hashim Badr, blamed Washington, London and Ottawa for the failure to achieve consensus, saying it was a "sad day for the NPT."
Last month, Egypt, backed by other Arab and non-aligned states, proposed that UN Secretary-General Ban Ki-moon convene a regional conference on banning weapons of mass destruction (WMD) as called for at the 2010 NPT review. The conference would be with or without Israel's participation, without agreement on an agenda and with no discussion of regional security issues.
Those conditions are unacceptable to Israel and Washington.
Decisions at NPT review conferences, which are held every five years, are made by consensus.
Israel neither confirms nor denies the widespread assumption that it controls the Middle East's only nuclear arsenal. Israel, which has never joined the NPT, agreed to take part in the review meeting as an observer, ending a 20-year absence.
The call for a 2012 conference on a regional WMD ban, approved at the 2010 NPT review meeting, infuriated Israel. But diplomats said Israel eventually agreed to attend planning meetings. The 2012 conference never took place, which annoyed Egypt and other Arab states.
Egypt's proposals, Western diplomats say, were intended to focus attention on Israel. Washington and Israel say Iran's nuclear programme is the real regional threat.
Iran says its programme is peaceful. It is negotiating with world powers to curb it in exchange for lifting sanctions.
Israel has said it would consider joining the NPT only once at peace with its Arab neighbours and Iran.
There were disagreements on other aspects of the NPT but delegates said the Middle East issue was the most divisive.