“My name’s Shrek,” said the soldier, his eyes glazed and staring as he cradled his Kalashnikov rifle.

The nickname given by his comrades to the bald, pug-eared soldier was the only moment of light relief during a day of tense drama in which The Times witnessed Russia breaching the ceasefire agreement over South Ossetia at will.

At a checkpoint set up by the Russian Army on the approach to the city of Gori from the Georgian capital, Tbilisi, an armoured personnel carrier blocked the road and riflemen had fanned out in the surrounding bushes, their weapons trained on anyone who approached.

All were ethnic Chechens, whose reputation for pitiless brutality in war made them feared throughout the Caucasus.

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The checkpoint was the first evidence that the deal brokered hours earlier by President Sarkozy of France was being ignored. Shortly after President Saakashvili had signed the agreement, Russian tanks and troops rolled into Gori.

The ceasefire had specified that both the Georgian and Russian armies should withdraw after the five days of bitter fighting. But the Russians had moved up to twenty tanks, armoured personnel carriers and hundreds of soldiers miles into Georgia to occupy Gori and take control of the road leading to Tbilisi.

One soldier, Yuri, said that his unit, part of the 42nd Chechen Division, had fought for the whole five-day campaign to wrest South Ossetia from Georgian control. Asked why they had taken Gori now, he said: “We were given an order and we are following it. We don’t know how long we will be here.”

Smoke rose behind him as buildings burnt in the villages surrounding Gori. There were also prolonged bursts of automatic gunfire, although Georgian troops had abandoned the city in a panic on Monday night.

A stream of Georgians fled the area in cars, tractors and lorries, taking what belongings they could. A black Volga car crammed with passengers carried two more escapers on its roof.

One elderly couple were walking, the woman clearly in shock, her face swollen and one eye badly damaged. She pointed backwards and said: “They are killing people there, the Chechens and the Ossetians.”

Irregular soldiers from South Ossetia were being accused yesterday of killing and looting, acts of revenge for the Georgian incursion on Friday that the Russians say cost 2,000 lives. The irregulars, mostly young, twitchy and armed by the Russians, were identified by white bandage strips tied around their sleeves. Some wore black balaclavas.

Then, suddenly, a convoy of about seventy Russian military vehicles – some carrying antiaircraft guns and all loaded with soldiers and irregulars – began to pour out of Gori and head towards the capital.

Russian flags flew from several of the vehicles. Some irregulars shouted that they were on their way to Tbilisi.

The convoy continued south for almost ten miles, unchallenged by the Georgian forces, which had withdrawn from Gori to Tbilisi. Just as it seemed that they might really be intent on reaching the capital, the vehicles turned left towards the village of Orjosani.

Irregulars jumped out to form a security cordon. Asked what their mission was, they said only that they had been ordered to advance to the village and await instructions.

Tengiz, a 23-year-old South Ossetian, brandished his gun and said: “If I had the chance I would go all the way to Tbilisi now, but there is a peace agreement so they don’t let us.”

Several army trucks had become detached from the main convoy and arrived after it had turned into the wooded lane leading to Orjosani. Oblivious, they ploughed on towards Tbilisi, now only a little over 30 miles away, before realising their error and making a sharp U-turn.

Six or seven miles up the road, and no more than twenty-five miles from Tbilisi, Georgian soldiers were scrambling to establish artillery positions. They had been caught out by the unexpected Russian movement and they had been scrambled from the capital to set up a defensive line.

“We have instructions not to allow the Russians to come any closer to Tbilisi,” one soldier said. “If they come here, we will shoot.”

Another soldier, kitted out in American fatigues, said: “If we don’t wait for them here, they will come straight to Tbilisi. We have no other choice. We are ready to fight.”

The ceasefire – less than a day old – was already hanging by a thread, and Russian troops had advanced farther into Georgian territory than at any point during the war. Already victorious militarily, the Russian Army appeared determined to humiliate Georgia by demonstrating that it alone would decide where to go and when.

Yesterday’s events also raised deeper questions about the value of the Russian President’s word. Dmitri Medvedev signed the ceasefire agreement but was clearly failing to enforce it.

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