Iraq accused Iran of killing an Iraqi soldier and harassing one of its ships in the Persian Gulf after a United Nations-mediated cease-fire took effect on Saturday.

The official Iraqi news agency INA said an Iranian sniper shot Private Khalil Ibrahim Latif at Saif Saad in the central sector of the war front, more than three hours after the ceasefire deadline.Iraqi troops did not return fire but told U.N. military observers, one of whom inspected the scene, INA said.

The agency said earlier Iranian helicopters and a warship shadowed the merchant ship Khawla as it sailed into the Strait of Hormuz from a port outside the Gulf in the United Arab Emirates.

It said this was a clear violation of the ceasefire and Baghdad had protested to Maj. Gen. Slavko Jovic, commander of the U.N. military observer team.

Iran said its naval patrols intercepted and searched the ship when it entered the strait. Iran's navy commander, Rear Adm. Mohammad Hossein Malekzadegan, said it was allowed to proceed.

"This is the normal course of action over the past few years concerning all ships which cross the Strait of Hormuz," said Malekzadegan, quoted by the Iranian news agency IRNA.

Iraqi Foreign Minister Tareq Aziz, quoted by Iraqi television, told Jovic: "If Iran interferes with Iraqi shipping in any way, Iraq will not submit but will resist strongly."

Jovic, the Yugoslav officer heading the observers sent to Iran and Iraq to monitor the cease-fire, told reporters earlier in Baghdad the cease-fire was holding.

At Moslem prayer times, 101-gun artillery salutes boomed out across Iraq to greet the cease-fire at the front, where the rival armies were virtually back at their border positions of nearly eight years ago.

"I am most happy to inform you the ceasefire is in operation on both sides," said Jovic. "We deployed our forces. They are in their places."

The Khawla was one of three ships, including an oil tanker loaded at one of Iraq's long-idle Gulf terminals, sent into the waterway to exercise what INA called Iraq's "natural rights to free navigation in the Strait of Hormuz and international waters."

Iran said on Friday it would continue to inspect shipping in the Gulf until it achieved a comprehensive peace, but the commander of the Iraqi navy told INA he hoped the Iranian statement was a "slip of the tongue."

Iraqi Oil Minister Issam Abdul-Rahim al-Chalabi announced that oil exports would resume immediately from ports unused since Iran blasted them in the early days of the war.

Baghdad Radio announced a "beautiful morning" after the capital's residents spent a jubilant night in the streets honking horns, spraying water and shaking tambourines.

Blue-helmeted U.N. observers patrolled the battle zones where an estimated million soldiers died in one of the longest and deadliest wars of modern times.

The 350-man U.N. Iraq-Iran Military Observer Group (UNIIMOG) deployed its full strength at the front to show its presence.

"At this hour, on this beautiful morning, the deadline for a comprehensive peace between Iraq and Iran in the air, on land and at sea has passed," proclaimed Baghdad Radio at 7 a.m. local time (9 p.m. MDT Friday).

"Doors are now open for those who want peace, justice and love," it said. "Iraqis and Arabs have the right to celebrate this great victory."

Tehran Radio called Saturday "a special day which opens a new chapter in the history of Iran and the Islamic revolution."

But it added: "Just as acceptance of the cease-fire resolution was not tantamount to ending the war, implementation of the cease-fire will not close the file on the war either."