May 24 (UPI) — The United States on Sunday blamed the collapse of a U.N. nuclear nonproliferation conference on what it called some countries’ inability to take Iran’s threat to global nonproliferation seriously.

The nearly monthlong Review Conference of the Parties to the Treaty on the Nonproliferation of Nuclear Weapons ended Friday without consensus on an outcome document, which reviews implementation of the Cold War-era pact and sets recommendations and commitments for its 191 state parities.

Conference President Do Hung Viet of Vietnam said Friday, following weeks of work and four versions of an outcome document, that he would not put it forward for adoption as “the conference is not in a position to achieve agreement on its substantive work.”

The failure came amid mounting global insecurity, including the war in Iran, the modernization and expansion of nuclear arsenals and other geopolitical tensions, which complicated efforts to reach consensus.

The U.S. State Department on Sunday faulted on other NPT member states.

“The inability of some NPT States Parties to take Iran’s threat to global nonproliferation seriously will be addressed by the United States in our continuing engagements,” State Department spokesperson Thomas Pigott said in a statement.

He said the failure to adopt a document was made worse by what he described as Iran’s continued noncompliance with NPT-required safeguards and “its escalating nuclear activities.”

Pigott did not specify in the statement which activities he was referring to. The United States attacked Iran’s nuclear facilities in June, with President Donald Trump repeatedly claiming they were “obliterated.”

“For the NPT Review Conference to uphold its founding mandate, States Parties cannot turn a blind eye to Iran’s noncompliance, nor can violators be allowed to undermine the enforcement and accountability mechanisms at the core of the NPT,” he said.

Iran was quick to blame the United States, saying Washington’s “excessive demands” were at fault.

The United States was seeking to include language in the document concerning Iran, which accused the United States during the meeting of violating the treaty by attacking its nuclear facilities.

“The NPT Review Conference failed for the third consecutive time due to obstructionism by the United States and its allies,” Iran’s mission to the U.N. said in a social media statement.

Following the collapse of the conference, U.N. Secretary-General Antonio Guterres expressed his “disappointment.”

“The current international environment, marked by deep tensions and an elevated risk posed by nuclear weapons, demands urgent action,” his spokesperson, Stephane Dujarric, said in a statement.

“The secretary-general appeals to all states to make full use of all available avenues of dialogue, diplomacy and negotiation to reduce tensions, lower nuclear risks and, ultimately, eliminate the nuclear threat.”

It is the 11th meeting of the treaty states parties and the third in consecutive review conference to end without an agreement.

Daryl Kimball, executive director of the Arms Control Association, said the failure of the conference to call for “urgently needed” concrete actions to avert a new nuclear arms race was due to the five nuclear-armed states’ use of “aggressive diplomatic intimidation tactics against non-nuclear weapons states.”

He also said U.S. leadership as “sorely lacking.”

“The foundations of the NPT, the cornerstone of global efforts to reduce and eliminate the world’s greatest danger, are cracking due to inattention, intransigence and ineptitude,” Kimball said in a statement.