As U.N.-mediated cease-fire talks began, Iran's foreign minister accused Iraq of trying to sabotage peace efforts with attacks he said involved the "large scale" use of chemical weapons.

"We said (to Secretary-General Javier Perez de Cuellar) that if (the Iraqis) continue their attack, we will give them a lesson that they won't forget," Ali Akbar Velayati said Tuesday after meeting twice with the U.N. chief.The Iranian and his Iraqi counterpart, Tariq Aziz, were meeting separately Wednesday with Perez de Cuellar.

Velayati told reporters that he discussed with Perez de Cueller a timetable for implementing the year-old U.N. cease-fire plan that his country agreed to accept last week. "We also talked about the recent escalation of the war," he said.

Perez de Cuellar said he dispensed with formalities and began peace talks Tuesday, one day ahead of schedule, because Velayati had already arrived.

Velayati and Perez de Cuellar discussed implementation of Security Council Resolution 598, which was passed unanimously on July 20, 1987, and demands an immediate cease-fire in the 8-year-old Iran-Iraq war. The plan also calls for withdrawal to internationally recognized borders, prisoner exchanges, peace negotiations and an investigation to determine which side started the war.

Iraq this week announced its forces were withdrawing from the area just north of Khorramshahr, an Iranian port city.

But the official Islamic Republic News Agency, monitored in Nicosia, said Wednesday that at least 300 Iraqis were killed or wounded in fighting in the area, and dozens of tanks or armored personnel carriers were destroyed.

Perez de Cuellar has said that he hopes he can announce next week the dates for a cease-fire.

Meanwhile, two U.N. teams were at work in Tehran, one laboring over truce details, the other inquiring into the prisoner-of-war situation.