Nothing disturbed the silence as two United Nations military observers gazed across rocky, sunbaked hillsides at Iranian lines a few miles from the deserted Iraqi village of Qoratu.

"It's just quiet on both sides. Nothing has happened yet," blue-bereted Norwegian Capt. Arne Ophus told reporters. "As you see, we aren't even wearing our helmets. But they are in the car if we need them."

He and his Malaysian colleague, Major Shahrir bin Abdul-Malik, are stationed on the central sector of the Iran-Iraq war front where a U.N.-sponsored cease-fire silenced the guns after eight years of fighting.

At the nearby border town of Khanaqin a coffee shop owner said residents had started to filter back to their shell-shattered houses over the past few days.

"Even those who left before the shelling are coming back," he said.

The U.N. team's Yugoslav commander, Maj. Gen. Slavko Jovic, said in Baghdad that the ceasefire that took effect at 11 p.m. EDT on Friday was holding.

"The cease-fire is operational," Jovic said. His officers were investigating an Iraqi charge, denied by Tehran, that an Iranian sniper shot dead an Iraqi soldier after the cease-fire.

The 350-man, 24-nation U.N. Iran-Iraq Military Observer Group (UNIIMOG) has to keep the peace along a 740-mile line running through mountains, deserts and marshes.

Ophus, 42, said the U.N. team was thinly stretched. "Only two of us look after a sector 90 miles long," he said.

Seven pairs of observers from 10 nations were working in shifts around the clock to cover the front line near Qoratu, 105 miles northeast of Baghdad.

Apart from the sheer distances, he said, problems included language, communications and the nature of the terrain.

Men from Canada's 88th Signals Squadron are struggling to set up independent communications but so far the observers are relying on radios in their vehicles, provided by the Iraqi army.

"An advance party inspected the area today and communications will be set up tomorrow," said Canadian Maj. Alexander Carruthers, duty officer at the town of Baaqouba, one of the U.N. team's three forward bases in Iraq. The others are at Basra in the south and Kirkuk in the north.

"Communications are satisfactory and improving all the time," Irish Col. William Phillips said at U.N. headquarters in Baghdad. "We are in touch with the key people."

The observers' mandate under Security Council resolution 598 is to "verify, confirm and supervise" the cease-fire and the withdrawal of opposing forces to internationally recognized borders.

One of their challenges is to locate the frontier. "We don't know exactly where the border is," said Ophus, gesturing at a barren expanse of no-man's land.