UNITED NATIONS, NOV. 2 -- Iran and Iraq each replied in writing today to the latest U.N. request for compliance with the Security Council's July cease-fire demand, but diplomats involved in the process said both responses reflected a hardening of positions rather than a narrowing of differences.

The two belligerents in the seven-year Persian Gulf war responded to a nine-page outline submitted two weeks ago by Secretary General Javier Perez de Cuellar, who was acting on instructions from the council.

Iran's reply, the sources said, continued to insist that the formal cease-fire be concurrent with a verdict by a commission, yet to be created, condemning Iraq for launching the war. An informal truce, "on the basis of understandings," could begin simultaneously with the naming of the commission, Tehran said.

In a new condition, Iran linked troop withdrawal to the payment of reparations by Iraq and warned that since Baghdad's 1980 invasion nullified a 1975 border treaty, the frontiers must be redefined before withdrawal can take place.

Iranian Ambassador Said Rajaie-Khorassani said his government's three-page response was "positive." He said it "has certain comments with regard to the points" in the secretary general's outline.

The outline detailed the elements of the resolution that remained unresolved, including the timing of a cease-fire, a withdrawal of forces to frontiers, a prisoner exchange and creation of the commission to establish responsibility for the war.

Iraq had initially accepted the July resolution on condition that Iran do the same. Today, however, the sources said, Iraq demanded that a truce and withdrawal must be a first step before discussion of the details of a fault-finding commission, or other measures.

Ambassador Ismet Kittani said, "The first step is the cease-fire and the withdrawal to recognized international boundaries, and then we can talk about the second, third, fourth and fifth steps."

Perez de Cuellar provided the responses to Japan, the council president for November, and to the council's five permanent members -- Britain, France, China, the Soviet Union and the United States. They appeared to agree that, as one of their envoys put it, "both sides are now dragging their feet."

Perez de Cuellar reportedly still wants to invite high-ranking Iranian and Iraqi officials to New York to embark on an indirect dialogue, in hopes of working out terms acceptable to both sides. Iraq is said to have agreed to this, adding that the move could only come after an Arab League meeting that is to begin Sunday in Amman, Jordan.

American officials have maintained that without a viable threat of sanctions, such as an arms embargo, Iran will not be responsive to the cease-fire demands.

So far, however, most other council members have been reluctant even to discuss the terms of a possible embargo and have urged instead that the negotiation process be tilted closer to the Iranian demands. That shift, already reflected in the council's mid-October instructions, diplomats suggested, may have been one reason for the hardening of the Iraqi position today.