UNITED NATIONS (AP) — The U.N. General Assembly has overwhelmingly approved a resolution calling on Israel to quickly open its nuclear program for inspection and backing a high-level conference to ban nuclear weapons from the Middle East which was just canceled.

All the Arab nations and Iran had planned to attend the conference in mid-December in Helsinki, Finland, but the United States announced on Nov. 23 that it wouldn’t take place, citing political turmoil in the region and Iran’s defiant stance on nonproliferation. Iran and some Arab nations countered that the real reason for the cancellation was Israel’s refusal to attend.

The resolution, approved Monday by a vote of 174-6 with 6 abstentions, calls on Israel to join the Nuclear Nonproliferation Treaty ‘‘without further delay’’ and open its nuclear facilities to inspection by the International Atomic Energy Agency. Those voting ‘‘no’’ were Israel, the U.S., Canada, Marshall Islands, Micronesia and Palau.

Resolutions adopted by the 193-member General Assembly are not legally binding but they do reflect world opinion and carry moral and political weight.

Israel refuses to confirm or deny it has nuclear bombs though it is widely believed to have a nuclear arsenal. It has refused to join the Nuclear Nonproliferation Treaty, or NPT, along with three nuclear weapon states — India, Pakistan and North Korea.

The Arab proposal to create a weapons-of-mass-destruction-free zone in the Mideast, and to pressure Israel to give up its undeclared arsenal of perhaps 80 nuclear warheads, was endorsed at an NPT conference in 1995 but never acted on. In 2010, the 189 parties to the 1970 treaty called for convening a conference in 2012 on the establishment of a WMD-free zone in the Middle East.

The resolution, which was approved by the assembly’s disarmament committee before the conference was cancelled, noted the decision to hold it ‘‘with satisfaction.’’

But Israel has long said there first must be a Mideast peace agreement before the establishment of a Mideast zone free of weapons of mass destruction. The region’s Muslim nations argue that Israel’s undeclared nuclear arsenal presents the greatest threat to peace in the region.

The Israeli government had no immediate comment on Monday’s General Assembly vote.

Last week, the General Assembly upgraded the Palestinians to that of a nonmember observer state, endorsing an independent Palestinian state in the West Bank, east Jerusalem, and the Gaza Strip.

Just before Monday’s vote, Iranian diplomat Khodadad Seifi told the assembly ‘‘the truth is that the Israeli regime is the only party which rejected to conditions for a conference.’’ He called for ‘‘strong pressure on that regime to participate in the conference without any preconditions.’’

Israeli diplomat Isi Yanouka said his country has continuously pointed to the danger of nuclear proliferation in the Mideast, singling out Iran and Syria by name.

‘‘All these cases challenge Israel’s security and cast a dark shadow at the prospect of embarking on a meaningful regional security process,’’ he said.

‘‘The fact that the sponsors include in this anti-Israeli resolution language referring to the 2012 conference proves above all the ill-intent of the Arab states with regard to this conference,’’ Yanouka said.

Syrian diplomat Abdullah Hallak told the assembly his government was angry that the conference wasn’t going to take place because of ‘‘the whim of just one party, a party with nuclear warheads.’’

‘‘We call on the international community to put pressure on Israel to accept the NPT, get rid of its arsenal and delivery systems, in order to allow for peace and stability in our region,’’ he said.

The conference’s main sponsors are the U.S., Russia and Britain. British Foreign Office Minister Alistair Burt has said it is being postponed, not cancelled.