Georgia asserts that it began shelling the South Ossetian capital of Tskhinvali after four villages under Georgian control came under attack after a cease-fire declared on Aug. 7.
Ryan Grist, head of a team of monitors for the Organization for Security and Cooperation in Europe (OSCE), said that while his team members had not visited the villages, they did not hear any shelling in the one closest to Tskhinvali.
"If there had been any provocations, the response from the Georgian side was disproportionate," Mr. Grist said.
A human rights monitor in conflict zones for 16 years, Mr. Grist resigned shortly after the August war. He would not give a reason.
Rights groups have accused both Georgia and Russia of using indiscriminate force that killed and injured civilians.
Both sides said they were aiming at specific military targets, but they used non-precision weapons.
Russia has reported 159 civilian and 64 combatant deaths including South Ossetian forces. Georgia said 220 civilians and 185 soldiers died and 2,234 were wounded, of whom 1,964 were combatants.
The London-based rights group Amnesty International said in a report released last week that "serious violations of both international human rights law and international humanitarian law were committed by all parties."
Human Rights Watch reached a similar conclusion, but has not published its report yet, said Giorgi Gogia, a researcher in its Tbilisi office.
Residents of the region were used to violence after 15 years of intermittent shelling and shooting, but neither Georgians nor Ossetians were prepared for cluster bombs, massed artillery barrages and bombing.
Georgia and Russia disagree over who started the fighting.
Georgia says it broke a self-imposed cease-fire — announced by President Mikhail Saakashvili at 7 p.m. on Aug. 7 — to respond to Russian firing on Georgian-controlled villages from South Ossetian lines.
"Russia started the shooting; Russia started the invasion," Mr. Saakashvili said in a recent interview with The Washington Times.
However, there is no definitive evidence of when Russian soldiers and armored vehicles entered South Ossetia. The Georgian government claims they arrived by midday Aug. 7. Russia says its forces entered on Aug. 8 only after Georgia shelled the South Ossetian capital.
Secretary of State Condoleezza Rice, in a Sept. 18 speech, said the fighting began "following repeated violations of the cease-fire in South Ossetia, including the shelling of Georgian villages." But she continued, "the Georgian government launched a major military operation into Tskhinvali and other areas of the separatist region."
The Georgian government has not said that Russian combat troops were in the capital, Tskhinvali, when it began its artillery barrage.
Three OSCE monitors and local staff were in their homes around Tskhinvali when the barrage began. Mr. Grist said they told him over the phone that there were explosions every 15 to 20 seconds.
At 11:40 p.m., "explosions of undistinguishable origin" buffeted Lira Tskhovrebova's house in Tskhinvali. She and her husband crouched in the corners of a hallway until the shelling stopped the next morning.
"I understood that God loves me, because my children were not with us," she said.
Alexandre Lomaia, secretary of Georgia's national security council, told a parliamentary commission that Georgian forces fired at military targets using precision weapons.
However, Amnesty International reported that Georgia used "Grad" multiple-rocket launchers and found damage a quarter-mile away from any military target.
In the week before full-fledged fighting erupted, both sides exchanged light arms and mortar fire. Small skirmishes have kept the conflict simmering since a 1992-93 war between separatists and Georgia.
Kurta, a Georgian-controlled village, was the target of mortar and light arms fire from South Ossetian lines on Aug. 6 and 7, including after the cease-fire had been announced, according to several villagers.
"What cease-fire? It was announced, but there was no cease-fire. There was still fighting," said Gocha Nabardinshvili, 29, who lived in Kurta with his parents and two brothers.
Budiko Kandelaki, a former second secretary of the Communist Party in Tskhinvali, said a mortar shell from South Ossetian lines on Aug. 3 ripped through his house in Nikosi, about half a mile south of Tskhinvali. Nikosi came under heavier shelling from South Ossetia on Aug. 6, he said.
"There'd never been anything like on the 6th before," he said.
A combined patrol by peacekeeping forces and the OSCE confirmed "isolated incidents" of mortar fire on Nikosi before the war, Mr. Grist said.
The Russian government acknowledges that it bombed military targets in Gori and Georgian villages from Aug. 8 to 11.
Kelly Uphoff, a Peace Corps volunteer living in Gori, was on the street when jets passed overhead on the morning of Aug. 8. She heard the whistle of falling bombs, and started running.
"You didn't know which way to run. You couldn't see where the bomb was going," said Ms. Uphoff, 25. She and her co-workers hid in the basement of their office.
Amnesty International found several instances of bombing of civilian areas in Gori. Ms. Uphoff said bombs hit a wedding hall, three apartment buildings and a furniture storage building for Gori University.
"Either their intelligence was off or their aim is terrible," she said. She left before the town was occupied by Russian and South Ossetian forces on Aug. 11.
Russia has recognized South Ossetia and another breakaway enclave, Abkhazia, as independent states. Russian President Dmitry Medvedev said in Washington last week that Russia would have nothing to do with Georgia while Mr. Saakashvili is in charge.
The United Nations says nearly 200,000 people were driven from their homes by the fighting. Most have returned, but Amnesty International estimates 24,000 people are still displaced and says the atmosphere along the border remains tense.
Many of these people are ethnic Georgians who had lived in South Ossetia.
In Nikosi, Mr. Kandelaki held a bottle of pills for calming his heart while he showed a reporter the battle scars of his home.
During the fighting, South Ossetian paramilitary fighters tied him to a tree in his yard, and Russian soldiers found and untied him later, he said.
"The ones in uniform were fine. Ossetian, Russians ... in a uniform, they were decent. But the ones in civilian clothes, they were different," he said.
They stole most of his possessions.
"I'd offer you wine, but I have none," he said. "Not even glasses."