Iran and Iraq returned to the negotiating tables Friday for talks aimed at ending their 8-year-old war. The U.N. secretary-general expressed confidence they will achieve peace but said it won't be easy.

Secretary-General Javier Perez de Cuellar told reporters before he entered the meeting that he was certain both sides "sincerely want to solve the problem."However, he added "that is a problem that has lasted many years, I would say centuries, and it is not in one afternoon that we can decide."

Thursday's session was the first face-to-face meeting between envoys of the bitter enemies since the beginning of the war that has killed or wounded more than 1 million people. After a direct negotiating session, the delegations went into separate rooms, with Perez de Cuellar in a room in the middle.

Friday's talks began about one hour late, after the arrival of Iranian Foreign Minister Ali Akbar Velayati. He refused to answer questions from reporters. The Iraqi delegation, led by Foreign Minister Tariq Aziz, arrived about 40 minutes late and did not answer questions.

Perez de Cuellar said the delegations would continue to sit in separate rooms, with the U.N. team in a third room in the middle, consulting separately with them. He said it was "still too difficult" for any other arrangement.

The U.N. chief said the arrangement was made at the request of the two countries. "I would prefer to have them all the time in the main room with me." But he said, "I have to accommodate myself to the wish of the parties."

Perez de Cuellar called Thursday's five-hour plenum and separate discussions good and serious. "Your presence clearly indicates your governments are prepared to pursue the path of peace," he told the delegations.

After the formal U.N.-sponsored joint discussions Thursday, the delegations consulted in separate rooms for three more hours. They were joined by U.N. officials who reported back to the secretary-general.

Perez de Cuellar said both sides "decided to discuss seriously, with no rush." He added, in answer to a question, that it was "too early to be optimistic."

The peace process is expected to be long and difficult, possibly lasting for years. The direct talks were made possible after Iran and Iraq both accepted U.N. Security Council Resolution 598, calling for a cease-fire in the war.

Before the talks began, Perez de Cuellar held several meetings with Aziz and Velayati in New York. The warring sides agreed to hold direct talks following a cease-fire, which began Aug. 20.

The truce appeared to be holding. Saeem Fahmawi, a spokesman for the 350 U.N. observers monitoring the 733-mile Iraq-Iran war front, said in Baghdad there have been no major violations.

The Iranian and Iraqi delegations in Geneva include political figures, military representatives and legal experts on war relief, prisoner repatriation and reparations.