Russian lorries taking humanitarian aid to conflict-hit eastern Ukraine have started a second day of their journey.
The 262-vehicle convoy stopped overnight in the southern city of Voronezh, and is expected to arrive at the Ukraine border later on Wednesday.
Uncertainty remains about how the aid will be delivered, amid fears Russia could use the convoy as a pretext for military action in Ukraine.
At least 1,500 have died since Ukraine sent troops against pro-Russia rebels.
The fighting in the Donetsk and Luhansk regions since mid-April has displaced almost 300,000 people, many of whom have fled to Russia.
Meanwhile Russian President Vladimir Putin is expected in Crimea on Wednesday for a meeting with members of the Security Council.
Russia annexed Crimea from Ukraine in March, a move which triggered the first round of Western sanctions against Moscow.
Ukraine conditionsThe lorries, said to be carrying nearly 2,000 tonnes of aid, left the Moscow area bound for Luhansk on Tuesday morning.
Russian TV showed the cargo, including grain, baby food and medicine, which will go to civilians trapped by fighting in the area held by pro-Russia rebels.
Russian TV showed the aid being loaded onto lorries on Tuesday morning 
Residents in Donetsk and Luhansk are facing food shortages and power cuts because of the fighting 
Ukraine government forces continue to shell rebel areas 
Thousands are reported to be without water, electricity and medicine The convoy spent the night in Voronezh, about 300km (185 miles) or seven hours' drive from the proposed border crossing point at Shebekino-Pletnyovka into Ukraine's Kharkiv region, and is now continuing its journey.
On first hearing news of the convoy, Ukraine set conditions for its entry into Ukraine.
Security council spokesman Andriy Lysenko said aid should pass through a government-controlled border post and be accompanied by Red Cross officials.
Later Russian Foreign Minister Sergey Lavrov said Moscow had agreed to these conditions.
"We have received a note from the Ukrainian side with confirmation of their readiness to accept this aid," he said, quoted by Itar-Tass news agency.
Mr Lavrov added that a Ukrainian demand that the aid be transferred to other vehicles at the border had been dropped on the grounds of cost.
The lorries would continue on their journey with Ukrainian number plates, he added.
But the BBC's Daniel Sandford in Moscow says that long discussions are continuing about whether the lorries will actually be allowed to enter.
Western officials have expressed concerns that Russia is using humanitarian assistance as a pretext to put troops in eastern Ukraine.
The International Committee of the Red Cross (ICRC), meanwhile, has said it still needs more security guarantees and information about the aid convoy.
It has, however, acknowledged the situation in eastern Ukraine is critical and has agreed in principle to such an operation.
Casualties: At least 1,543 people have been killed in the east since mid-April, including civilians, the military and members of the armed groups, the UN said on 8 August. Some 4,396 have been confirmed wounded "but the real number is likely to be much higher". Ukraine said on 11 August that 468 of its soldiers had been killed. The rebels have reported losing at least 800 fighters.
Refugees: Nearly 300,000 people have been forced from their homes this year. More than 117,000 are displaced inside Ukraine, 87% of them from the Donetsk and Luhansk regions, while a further 168,000 have crossed into Russia. Source: UN refugee agency
Our correspondent says that such a theatrical move by the Russians, which involved painting lorries a bright white colour and driving them 800km, suggests the Russians are trying to make a point as much as send aid.
Many of the goods being supplied could be sourced much closer to eastern Ukraine, he says, but the Russians argue that Kiev has failed to look after the humanitarian needs of its people.
'Horrible losses'Ukraine has reported in recent days that Russia has massed 45,000 troops on its border.
However, Kremlin spokesman Dmitry Peskov described the idea of using the aid convoy as an excuse for military action as "absurd" and said the mission was purely humanitarian and non-military.
Advances by government troops in recent weeks have put pressure on the rebel-held cities of Donetsk and Luhansk, leaving the latter in particular virtually cut off.
However, Ukrainian media reported on Wednesday that a group of ultranationalists fighting on the side of the Ukrainian government had borne heavy casualties after an ambush near Donetsk.
Right Sector leader Dmytro Yarosh was quoted as promising retaliation after a combat group suffered "horrible losses".
The fighting has prevented a full investigation of the MH17 air disaster on 17 July, in which 298 people died.
It is strongly suspected that the plane was shot down by pro-Russian rebels. Russia and the separatists have blamed the Ukrainian military.
Are you, or your relatives in eastern Ukraine? Are you affected by events in this story? If you are willing to share your experiences and photos of the situation, email haveyoursay@bbc.co.uk with the subject heading 'Ukraine crisis' and include your contact details if it is safe to do so.
Send your pictures and videos to yourpics@bbc.co.uk or text them to 61124 (UK) or +44 7624 800 100 (International). If you have a large file you can upload here.
Russian aid convoy pushes south
Put the internet to work for you.
Or you can contact us using the form below.