UNITED NATIONS, DEC. 24 -- The 15 Security Council members said

today they are determined to consider imposition of sanctions, such as an arms embargo, to force Iran to comply with a U.N. cease-fire resolution designed to end the seven-year-long Iran-Iraq war.

The announcement stopped short of a commitment to the embargo promoted by the United States and other western nations, but it represented a step forward by the Soviet Union, China and others who had maintained that consideration of sanctions was premature.

The State Department welcomed the decision and immediately interpreted it as opening the way for the imposition of an arms embargo on Iran, a step it has been pressing since early fall.

In a statement, the department said the council "now recognizes and accepts the need to move urgently toward drafting and adoption of an enforcement resolution."

It added that this second resolution "would include an arms embargo on the party, or parties, not complying fully with" the July 20 cease-fire resolution.

Iraq had said it would accept that resolution, but Iran refused. Any enforcement measures presumably would be aimed at convincing Iran to accept a cease-fire.

Representatives of the council's five permanent members -- Britain, China, France, the Soviet Union and the United States -- agreed privately earlier this week to start drafting an arms embargo resolution to be put before the full council early next year.

American, British and Iraqi diplomats said they had detected a new Soviet willingness to join in applying increased pressure on Iran.

The Americans and Iraqis cautioned that the new Soviet mood must be put to the test, and cannot be taken at face value. They said they saw merit, however, in Britain's suggestion that Moscow's caveats on an embargo -- a call for creation of a U.N. naval force to police it, and for a meeting among the five-power military chiefs of staff to negotiate it -- might simply be "camouflage" designed to disguise a Soviet political concession and placate the Iranians.

The Soviets have asked that talks on a naval force take place parallel to those on an embargo, but have said the two issues need not be linked.

Today's joint statement was negotiated and announced by Soviet Ambassador Aleksander M. Belonogov, who holds the rotating council presidency this month.

To provide a "fresh and resolute impulse" for a resolution of the war, the statement said, and to express "grave concern" over the slow progress of negotiation, the council members reaffirmed their commitment to the July resolution as the only basis for a comprehensive settlement of the conflict.

U.N. officials said this was intended as a rejection of Iranian demands for an international commission to assess blame for the war and set compensation for damages before a declared cease-fire can take effect.

The council also called on Secretary General Javier Perez de Cuellar to pursue negotiations with both sides. His talks stalled earlier this month because of Iranian intransigence, he said.

Perez de Cuellar said today he would "renew his contacts with the two parties in the new year." Armed with the stronger threat of sanctions, a spokesman said, the secretary general will ask Iran and Iraq to restate their positions.

"I think we are closer to a practical arms embargo," said British Ambassador Crispin Tickell. "I hope it's a matter of weeks."

Belonogov said "we are moving in that direction," but added that "our acts will be governed by our assessment of consultations between the secretary general and the two belligerents."