A separate, larger convoy of around 270 Russian trucks, which Moscow claims is carrying aid, rumbled to a halt just short of the border on Thursday night, while in east Ukraine, shells hit the centre of rebel-held Donetsk for the first time.
The Telegraph witnessed a column of vehicles including both armoured personal carriers and soft-skinned lorries crossing into Ukraine at an obscure border crossing near the Russian town of Donetsk shortly before 10pm local time.
The Ukrainian and Western governments have long accused Russia of filtering arms and men across the border to fuel the separatist insurgency in Ukraine's Donetsk and Luhansk regions, but such an incident has never before been witnessed by Western journalists.
The convoy, which included at least 23 vehicles, appeared to be waiting until sunset near a refugee camp just outside Donetsk, before moving towards the crossing without turning off headlights or making any other attempt to conceal itself.
While it was not immediately clear whether all of that convoy crossed the border, The Telegraph did see a substantial number of vehicles pass through check point manned by gunmen after shadowing the convoy down narrow country lanes near the frontier.
While the force did not seem to be a substantial invasion force, it confirms that military supplies are moving across the border.
While the APCs carried no visible markings the fuel tankers and soft-skinned trucks in the convoy bore black Russian military number plates.
The vehicles do not appear to be associated with the Russian aid convoy that is camped 20 miles further down the same road.
Russia claims it wants to prevent a humanitarian crisis in eastern Ukraine, where civilians are caught in the crossfire in a conflict between pro-Russian separatist rebels and government troops that began in April.
Intense shelling on Luhansk and Donetsk left more than 25 people dead, while Ukrainian forces reported nine troops dead and 18 injured over the past day.
Igor "The Shooter" Girkin, the rebels' military commander, resigned from his post on Thursday.
He will be replaced by a senior militiaman known only as "The Tsar".
The separatists – who Ukraine and NATO say receive volunteers and weapons from across the border with Russia – have been on the back foot in recent weeks.
Besides Girkin, another senior rebel leader, Valery Bolotov, resigned yesterday saying it was due to injuries.
Vladimir Putin, Russia's president, said in a speech that Moscow wanted "to stop bloodshed in Ukraine as soon as possible".
Speaking in Yalta on the Crimea peninsula, which Russia seized from Ukraine in March, Putin added that, "the situation is becoming more dramatic by the day. The country has immersed itself in bloody chaos, a fratricidal conflict".
He stressed that Russians should avoid a rift with the West over Ukraine and "build our country, not fence it off from the outside world".
Kiev sees Moscow's calls for peace as deeply hypocritical and is suspicious of the aid convoy, which it believes is a possible covert invasion, or at least an attempt by Moscow to freeze a Ukrainian advance on rebel strongholds.
Russia's aid convoy is aimed at Luhansk, the worst-hit city, where residents have been without electricity and running water for several weeks, homes have been destroyed by artillery and mortar fire and food supplies are dwindling.
Under a tentative agreement between the two countries earlier this week the aid was supposed to be brought in to Ukraine at a border crossing near Kharkiv, in the northeast of the country, outside the conflict zone.
The International Committee of the Red Cross (ICRC) agreed to help with the handover and possibly with providing vehicles for the cargo to be transported across Ukrainian territory.
However, that agreement collapsed amid bitter recriminations on Wednesday, and on Thursday the convoy struck south to Kamensk-Shakhtinsky, close to the rebel-controlled portion of Ukraine's border with Russia.
The ICRC said that it would not facilitate the convoy if Russia decided to send the trucks into Ukraine without permission.
"Talks between the two sides are continuing but we can't help unless they come to an agreement," said Victoria Zotikova, a spokesman.
Laurent Corbaz, the organisation's head of operations for Europe and Central Asia, is due to travel to Kiev on Friday and Moscow early next week for talks over the convoy.
For a short time on Thursday it looked as if Vladimir Putin had resolved to send the aid mission straight across the border, in spite of Ukrainian objections.
After leaving Voronezh, the 270-vehicle convoy barrelled south towards Rostov-on-Don – a major city that could serve as another staging point.
But halfway the vast column of white-painted lorries and support vehicles took a westward turn towards the border town of Donetsk – not to be confused with the Ukrainian city of the same name – where Ukrainian forces have lost control of the border and rebels rule the land.
In a choking cloud of dust, the white-painted lorries crawled off the road and lumbered into place in serried lines on the parched field.
The drivers, in their unmarked khaki uniforms of baseball cap, T-shirt and slacks, slipped out of their cabs and made for the makeshift showers set up by soldiers from a neighbouring army base.
Luhansk was just a few hours drive a way.
There appeared little reason the trucks could not press on.
Military police, two army helicopters, and a number of unmarked vehicles bearing the black-number plates of the Russian ministry of the defence were escorting the convoy.
But instead the vehicles parked up at an army base about 30 miles short of the frontier.
"We didn't try at Kharkiv yesterday, the Ukrainian's wouldn't let us through," said one older, khaki-clad man in glasses who was talking with an airborne officer from the base.
"We just go where we are told, to deliver this aid."
The drivers The Telegraph spoke to said they had no idea where they would be sent next.
Neither the men in beige, nor the soldiers, made attempt to prevent journalists from wandering the site as lorries pulled in.
If anything, they were keen to show off their cargo, apparently in a bid to dispel accusations from some Ukrainian officials that the convoy may contain something sinister.
Two trucks, chosen at random by The Telegraph, proved to contain sacks of buckwheat and cardboard boxes full of sleeping bags – exactly the kind of aid Russia has insisted it is sending over the border.
But while there are no guns on display, the mission has a distinctly military flavor.
The drivers in khaki are clean-shaven service age males, and they drive originally army-green lorries that have been hastily spray-painted white.
At least one bore distinct tattoos normally associated with the armed forces.
Source: The Telegraph