The United Nations Security Council has rejected a U.S. resolution to extend an arms embargo on Iran that is due to expire in October, as Russian President Vladimir Putin proposed a summit of world leaders to avoid "confrontation" over an American threat to trigger a return of all UN sanctions on the Islamic Republic.

Only two of the Council's 15 members voted in favor, highlighting the division between Washington and its European allies since U.S. President Donald Trump withdrew from the nuclear accord in May 2018.

Besides the United States, only the Dominican Republic voted in favor of the draft. China and Russia voted against the text, and the remaining 11 Security Council members, including the European allies of the United States, abstained.

The result increases the likelihood that the U.S. will try to unilaterally force a return of UN sanctions, which experts say threatens to plunge the Council into one of its worst-ever diplomatic crises.

"The Security Council's failure to act decisively in defense of international peace and security is inexcusable," U.S. Secretary of State Mike Pompeo said in a statement.

According to UN Security Council Resolution 2231, the UN arms embargo on Iran will end on October 18.

The United States, which unilaterally announced its withdrawal from the Iran nuclear deal in May 2018, has repeatedly claimed it will invoke the "snapback" mechanism within the Security Council should its draft resolution fail to pass.

Iranian Foreign Ministry spokesman Abbas Mousavi called the U.S. isolation in the UN Security Council unprecedented.

"Throughout the 75-year history of the United Nations, the U.S. has never been so isolated, despite all its efforts and lobbying," he said.