UNITED NATIONS, AUG. 21 (TUESDAY) -- The five permanent members of the United Nations Security Council were working this morning toward an agreement that would permit U.N. members to use military action in enforcing the world body's sanctions against Iraq, diplomatic sources said.

However, an effort to push through a resolution during four hours of informal talks that began late Monday night stalled in the face of objections from Third World members of the 15-nation Security Council that they were being pressured to move too fast, the sources said.

U.S. officials said they expected their discussions with Britain, France, China and the Soviet Union to resume later today, but when asked about a specific time, U.S. Ambassador Thomas R. Pickering said only that the members had agreed to meet again "when all delegations have instructions."

The resolution under consideration would permit "minimum use of force" by the United Nations' 159 members to block all commerce between Iraq and the outside world. A U.S. diplomat said the effect would be to "put a U.N. umbrella but not a U.N. flag" over efforts by individual countries to enforce the far-ranging economic sanctions voted by the Security Council on Aug. 6 against Iraq and Iraqi-occupied Kuwait.

That means the resolution would give a U.N. stamp of approval to naval operations against vessels attempting to evade the sanctions, but it would keep the naval and other forces involved under the rules and command of their governments.

Pickering said the United States had requested discussions among the permanent members on an emergency basis because it had received intelligence that an Iraqi tanker loaded with oil was due to dock and unload in Yemen early today. But he added that Yemen, which is currently a member of the Security Council, gave assurances during the late night discussions that it would respect the sanctions against Iraq. That took the edge off the emergency, Pickering said, and allowed for postponement of a vote on the resolution.

The effect of affirmative U.N. action on the resolution would be to broaden international approval of the sanctions while ending the criticism that has been leveled against the United States and some of its allies for their independent efforts to interdict shipping bound for and from Iraq in the Persian Gulf and nearby waters. The critics have argued that only the Security Council can order such operations.

Libyan leader Moammar Gadhafi, who has been extremely critical of U.S. efforts to set up a naval blockade without first securing U.N. approval, said Monday that if the United Nations voted for a blockade, Libyan forces would support it.

Iran announced Monday that it will abide by a U.N. resolution ordering economic sanctions against Iraq, despite the newly established peace between the two neighboring countries. In a surprise move last week evidently aimed at winning Iran's support, Iraq's Saddam Hussein announced he would withdraw his troops from occupied Iranian territory and repatriate prisoners taken during the eight-year war with Iran.

Although the United States wants U.N. approval for its actions, it and its allies, such as Britain and France, do not want to relinquish control over their naval forces, a position that leads to the U.S. distinction about "umbrellas" as opposed to "flags."

The Bush administration and its allies are seeking a resolution that would permit some kind of loose cooperative arrangement among forces participating in interdiction but that would allow each individual country to chart its own course and set its own rules of engagement. For example, the United States might authorize its warships to fire warning shots across the bows of vessels in the area, while the Soviet Union might simply warn suspect ships that they could be evading the sanctions.

The council members favoring such action must draft a resolution that would not be based on Article 42 of the U.N. charter. Although that article permits the Security Council to order military action by U.N. members when there is a threat to world peace, it also would open the way to setting up some kind of multinational force under U.N. control.

The sources said one problem that must be resolved in drafting such a resolution is satisfying the Soviet Union's insistence that it will participate only in an action of a collective U.N. nature. The Soviets had talked of giving this role to the Security Council's military staff committee, but that also would raise the question of U.N. control over gulf forces.

The officials said the Soviets appeared willing to soften their conditions and accept a resolution containing language that specifies "collective action" but that does not mention the military staff committee.

A bigger question, according to the sources, involves China, which reportedly has argued that a naval blockade or other military action could jeopardize chances for a peaceful diplomatic solution to the crisis. The way China votes is important since no resolution can be passed without the approval of all five permanent council members.

The sources said China appears willing to abstain on a vote or perhaps to vote for a resolution if it feels a clear majority of Arab states sides with Kuwait and Saudi Arabia.

In any case, the sources said, there seems to be a strong consensus within the U.N. membership that Iraq's announcement that it would hold hostage thousands of foreign nationals trapped in Iraq and Kuwait must have a forceful response, including military measures to help ensure the effective operation of the sanctions.