"After they left, they sent down a team of Georgian special forces soldiers to discuss with the Russians access to the town.
"At that point the Russians, fearing some sort of assault was under way moved their tanks from the centre of town to the edge of the town."
A few minutes later the explosions, possibly from artillery fire, could be heard on the edge of Gori.
Meanwhile, more than 100 Russian vehicles were said to have massed 2km from the centre of Zugdidi, a major town in western Georgia, according to witnesses and Georgia's interior ministry.
Shota Utiashvili, a ministry spokesman, said: "The so-called Russian peacekeeping forces [deployed in the conflict zone], and Russia’s regular army units have entered Zugdidi and now control the local police headquarters."
Speaking by telephone from the city, Umit Bektas, a Reuters photographer, said: "I counted 104 Russian army vehicles, including 40 armoured vehicles, most of which are tanks."
Bektas said their purpose was unclear and that the convoy included weapons such as rocket-propelled grenades and was carrying Russian flags.
On Thursday, Medvedev hosted leaders of the de facto governments of South Ossetia and Abkhazia in Moscow where they signed the six-point plan, drafted by France, aimed at ending the hostilities.
He asked Eduard Kokoity, South Ossetia's president, and Sergei Bagapsh, his Abkhazian counterpart, to convey his support to the people of the respective regions.
"Please be aware that Russia's position is unchanged," Medvedev was quoted as saying by the Interfax news agency.
"We will support any decisions taken by the peoples of South Ossetia and Abkhazia... and not only do we support it but we will guarantee them both in the Caucasus and throughout the world."
In a statement made while the meeting was still ongoing, Sergei Lavrov, Russia's foreign minister, said that the question of Tbilisi's control over the regions was dead.
"One can forget about any talk about Georgia's territorial integrity because, I believe, it is impossible to persuade South Ossetia and Abkhazia to agree with the logic that they can be forced back into the Georgian state," he told reporters.
At a news conference in Moscow held after the meeting, Kokoity and Bagapsh said that they would push ahead with independence from Georgia.
"We will achieve independence in accordance with all of the rules of international law," said Kokoity.
"The aim [of independence] has been set and we will move toward it together," said Bagapsh.
Russian troops in tanks and armoured personnel carriers entered Gori on Wednesday, despite both sides signing a ceasefire agreement just hours earlier.
|Russian soldiers hold their positions on the streets of Gori [GALLO/GETTY]
"Despite the previously reached agreement, Russians are deploying additional forces in Gori and fortifying the city. At the same time, Russian armed forces have returned to Poti," Nato Chikovani, a spokeswoman for Georgia's foreign ministry, said on Thursday.
Tanks rolled back into the Black Sea port of Poti, where Russian forces sank a number of coast guard vessels on Wednesday, witnesses said.
"Just a few minutes ago they [the Russians] entered Poti in tanks," Nikoloz Gogoli, a shipping agent, told the Reuters news agency.
"Some of the guys have blue signs, badges, which means they should be peacekeepers."
Hoda Abdel-Hamid, Al Jazeera's correspondent in Poti, said there was no sign of Russian soldiers pulling back from the port.
Abdel-Hamid said: "The mayor of Poti has called it an occupation of western Georgia and said there were no signs of the Russian troops leaving the area.
"Although some of the soldiers wore insignia indicating they were Russian peacekeeping soldiers, many of them were proper Russian soldiers."
Shota Utiashvili, a Georgian interior ministry spokesman, said that Russian troops were "destroying" the two towns.
"The Russian troops are destroying the city of Gori. There are sounds of explosions. They are mining the city," he said.
"They are destroying everything in Poti port ... they are destroying the newly built roads in western Georgia."
Overnight Russian miitary officials had said that Gori, which sits on the only significant road between the east and west of the country, would be handed over to Georgian control.
|Lavrov said any looters from Russia or South Ossetia would be punished [AFP]
"Beginning [Thursday] the city's police will resume their work," Major-General Vyacheslav Borisov told Russian news agencies.
Borisov also defended his troops, and Russian-backed separatist forces from South Ossetia, from accusations of looting and invited Georgians to return to the town.
"All buildings are in normal shape, the town is supplied with water and electricity," he said.
Gori was battered by Russian bombing before the ceasefire, with Russian officials saying it was targeting a military base near the city.
Witnesses said that South Ossetian fighters, along with with some Russian army personnel, had gone house-to-house in villages near Gori torching homes and looting buildings.
Human Rights Watch said its researchers in South Ossetia had "witnessed terrifying scenes of destruction in four villages that used to be populated exclusively by ethnic Georgians".
Nazanine Moshiri, Al Jazeera's correspondent near Tskhinvali, the South Ossetian capital, said local Georgians had told her that Georgian villages in the area had been looted by South Ossetia militias while Russian troops looked on.
Moshiri said: "However, from a distance, we also saw large parts of the capital that appeared not to have been touched. The whole of the city appears to have been entirely occupied by the Russians."
Lavrov any looting would not be tolerated.
"I said from the very beginning that if any such facts prove true, we will react in the most serious way ... The peaceful population should be protected. We are investigating all these reports and will not allow any such actions," he said.
The ceasefire agreement drafted by France allows Russian forces to take unspecified "security measures", raising the possibility they could try to stay in Georgia proper under the justification of protecting their troops in South Ossetia.