Russia has "guaranteed" that no military personnel are on a convoy waiting at the border with Ukraine to deliver aid to the conflict-hit east of the country.
Ukraine has been concerned the convoy of about 260 white trucks could be a 'Trojan horse', which will allow Russia to set up a permanent presence in rebel-held territory.
Officials from the Red Cross have been examining the contents of the trucks on the Russian side of the border to make sure they contain nothing other than aid.
US Defence Secretary Chuck Hagel said he spoke with his Russia counterpart on Friday night and requested clarification on the convoy.
 Russian truck drivers check their vehicles, which are said to contain aid
 Russian truck drivers check their vehicles, which are said to contain aid  A statement released by the Pentagon, about the phone call between Mr Hagel and Sergey Shoygo, said: "Minister Shoygu 'guaranteed' that there were no Russian military personnel involved in the humanitarian convoy, nor was the convoy to be used as a pretext to further intervene in Ukraine.
"He acknowledged that the goods would be delivered and distributed under the International Committee of the Red Cross.
"Minister Shoygu assured Secretary Hagel that Russia was meeting Ukraine's conditions."
 Russian officials allowed journalists to see the contents of some trucks
 Russian officials allowed journalists to see the contents of some trucks  It came after Russia angrily denied it had sent a separate armed convoy into Ukrainian territory that Ukraine claims it partially destroyed.
Ukrainian President Petro Poroshenko said his forces had destroyed part of the convoy adding: "We won't tolerate any invasion."
Officials in Kiev said they tracked the vehicles, including armoured personnel carriers, from the border and then attacked with artillery.
 Ukrainian guards check people suspected of crossing the border illegally
 Ukrainian guards check people suspected of crossing the border illegally  The claim was partially verfied by journalists from the Guardian and Daily Telegraph newspapers who said they saw around 23 Russian military vehicles crossing the border near the town of Donetsk on Thursday night.
Sky's Foreign Affairs Editor Sam Kiley said any attack would mark "a very serious development" in the four-month conflict, and "could be the beginnings of something much more dangerous".
The US later said it was not able to confirm whether Kiev's forces had attacked the convoy, but said Russia had no right to send vehicles into Ukraine.
White House spokesperson Caitlin Hayden said: "Russia has no right to send vehicles, persons, or cargo of any kind into Ukraine, under any pretext, without the Government of Ukraine's permission."

Moscow's Defence Ministry dismissed Kiev's claim that it had sent a convoy into Ukraine as "some kind of fantasy".
Spokesman Igor Konashenkov told Ria Novosti agency: "There was no Russian military column, which allegedly crossed Russian-Ukrainian border, not in the night, not during the day, it just doesn't exist."
The European Union said it would consider any Russian incursion as "a blatant violation of international law".
Fighting continued on Friday with 11 civilians killed and eight more wounded by shelling in the besieged stronghold of Donetsk in 24 hours.
Ukraine's Foreign Minister Pavlo Klimkin is due to meet his Russian counterpart Sergei Lavrov in Berlin on Sunday to discuss the crisis.
 Azzez Hussein is heading back to the mountain to find his parents
 Azzez Hussein is heading back to the mountain to find his parents   Azeez's three-week-old daughter has had a traumatic start to her life
 Azeez's three-week-old daughter has had a traumatic start to her life   These Yazidis say they families would die if they waited for outside help
 These Yazidis say they families would die if they waited for outside help  
 A Kurd of the ethnic minority of Yazidis holds up a placard in Germany
 A Kurd of the ethnic minority of Yazidis holds up a placard in Germany   One option for the West is to work with the Kurdish Peshmerga troops
 One option for the West is to work with the Kurdish Peshmerga troops   US fighter jets have already conducted strikes in Iraq
 US fighter jets have already conducted strikes in Iraq   Shi'ite volunteers have joined the Iraqi army to fight against extremists
 Shi'ite volunteers have joined the Iraqi army to fight against extremists   Nouri al Maliki has bowed to pressure at home and abroad
 Nouri al Maliki has bowed to pressure at home and abroad   An RAF plane in a night drop of humanitarian aid to people on Mount Sinjar
 An RAF plane in a night drop of humanitarian aid to people on Mount Sinjar   A Yazidi figher who joined a Kurdish militia helps the safe passage
 A Yazidi figher who joined a Kurdish militia helps the safe passage  
 Members of the Yazidi sect hold a banner asking for international help
 Members of the Yazidi sect hold a banner asking for international help   Areas the Islamic State has launched offensives and wants to make one state
 Areas the Islamic State has launched offensives and wants to make one state   Mr Cameron at a UK aid Disaster Response Centre at Kemble Airport, earlier
 Mr Cameron at a UK aid Disaster Response Centre at Kemble Airport, earlier   The Russain aid convoy has turned towards Luhansk
 The Russain aid convoy has turned towards Luhansk   Self-styled mayor of Luhansk, Valery Bolotov, says he has been injured
 Self-styled mayor of Luhansk, Valery Bolotov, says he has been injured   Vladimir Putin says he wants to end the bloodshed in Ukraine
 Vladimir Putin says he wants to end the bloodshed in Ukraine   A Russian soldier stands guard at the Kharkiv checkpoint
 A Russian soldier stands guard at the Kharkiv checkpoint   Luhansk has been the scene of intense fighting
 Luhansk has been the scene of intense fighting   French President Francois Hollande's popularity has tumbled
 French President Francois Hollande's popularity has tumbled   Iraqi Christians receive food at Ainkawa's Saint Joseph church, near Irbil
 Iraqi Christians receive food at Ainkawa's Saint Joseph church, near Irbil   The boyfriend of Ms Mack's daughter, Tommy Schaefer, is led away by police
 The boyfriend of Ms Mack's daughter, Tommy Schaefer, is led away by police   Police examine the suitcase
 Police examine the suitcase   Ms Mack's daughter Heather, 19, is escorted from the premises
 Ms Mack's daughter Heather, 19, is escorted from the premises   Sky cameraman Mick Deane was killed in the violence
 Sky cameraman Mick Deane was killed in the violence   Human Rights Watch says more than 1,000 protesters were killed
 Human Rights Watch says more than 1,000 protesters were killed   The report implicates President Abdel Fattah al Sisi in the violence
 The report implicates President Abdel Fattah al Sisi in the violence   Men load sacks on to one of the 280 trucks headed towards Ukraine
 Men load sacks on to one of the 280 trucks headed towards Ukraine   US soldiers watch as halal meals are parachuted to the ground in Iraq
 US soldiers watch as halal meals are parachuted to the ground in Iraq   Yazidi refugees approach the food bundles on the ground
 Yazidi refugees approach the food bundles on the ground   Refugees flee the extremists carving a bloody path through northern Iraq
 Refugees flee the extremists carving a bloody path through northern Iraq   David Cameron has been urged to recall Parliament
 David Cameron has been urged to recall Parliament   A Palestinian woman returns to her destroyed home during a 72-hour truce
 A Palestinian woman returns to her destroyed home during a 72-hour truce   10,000 homes have been destroyed since July 8
 10,000 homes have been destroyed since July 8   Gazans inspect the damage after Israel's weekend bombardment
 Gazans inspect the damage after Israel's weekend bombardment  
 Smoke rises from the coastal side of the Gaza Strip after an Israeli strike
 Smoke rises from the coastal side of the Gaza Strip after an Israeli strike   A man sits amid the ruins of his home in Gaza
 A man sits amid the ruins of his home in Gaza   Abu Marzouk says the Palestinian delegation is ready to walk away
 Abu Marzouk says the Palestinian delegation is ready to walk away   A boy surrounded by rumble in a bombed out Gaza street
 A boy surrounded by rumble in a bombed out Gaza street  

