Lorries, part of a Russian humanitarian convoy, wait for permission to leave from the Donetsk-Izvarino customs control checkpoint for Ukraine on Aug. 21, 2014.
The Ukrainian Foreign Ministry has warned that separatists are shelling a possible route that a Russian humanitarian convoy could take to Luhansk.
"Attempts to establish contact between the General Staff of the Armed Forces of Ukraine and Russia, which is critical to ensure security for the convoy’s route, have failed, despite all attempts from the Ukrainian. Please note that terrorists are shelling the convoy’s possible route with mortars," the statement from the Ukrainian Foreign Ministry said.
Russia announced earlier on Aug. 22 that it was sending in a convoy of trucks with humanitarian aid into Ukraine without Kiev's approval.
In a statement Ukrainian President Petro Poroshenko called on Russia to bring events surrounding the convoy "back into the international legal framework."
The statement also said that the convoy's entrance into Ukraine without approval was illegal and in violation of international agreements.
New York Times reporter at the border checkpoint in Izvaryne, Andrew Roth, confirmed via Twitter that the last of the humanitarian convoy trucks had crossed into Ukraine from Russia.
Meanwhile Security Service of Ukraine Chief Valentyn Nalyvaichenko has called the passing of a Russian humanitarian aid convoy into Ukraine a "direct invasion."
"We call that a direct invasion. Under the cynical cover of the Red Cross these are military vehicles with cover documents," Nalyvaichenko told reporters in Kyiv on Friday.
Nalyvaichenko said the aid sent from Moscow is destined for Kremlin-backed insurgents, whereas the trucks themselves will be used to carry weapons for militants for use against civilians.
"These trucks will be used to transport equipment and weapons. Terrorists catastrophically lack, first and foremost, transport infrastructure after the successful actions of our military. These tractors are to be used for this purpose," he said.
Some experts, however, have called for Ukraine to exercise caution in order to stop events from escalating over the convoy.
"Keep calm everyone. Russia is provoking us into armed response in order to start a full-fledged invasion," said military expert Taras Berezovets on Facebook.
"The use of force has to be avoided. We need an asymmetrical response like blocking the road."
Russia’s foreign ministry warned Ukraine not to take any action against its humanitarian convoy that unilaterally crossed into Luhansk region without clearance from the border guard or the International Committee of the Red Cross (ICRC).
In a strongly worded statement on its website, the ministry said that the delays in clearance “have become unbearable” and blamed Ukraine’s authorities and their “manipulators from abroad” for creating artificial delays for the much-needed humanitarian cargo destined for eastern Ukraine.
“All excuses for blocking the delivery of aid to people in the area where this humanitarian catastrophe is happening have been exhausted. The Russian side has decided to act. Our convoy carrying humanitarian aid is beginning to move towards Luhansk,” Russia’s statement said.
The Associated Press meanwhile is reporting that the first aid trucks have already entered Ukraine via the rebel controlled border checkpoint at Izvaryne.
Ukraine's foreign ministry said that the convoy's border crossing was "illegal" and that Russia "ignored established international rules, procedures and achieved agreements." Kyiv, moreover, has repeatedly said that Russia could alleviate the humanitarian crisis by stopping military aggression against Ukraine, including the supply of army personnel, weapons, and hardware into the country.
"All responsibility for the safety of the loan is carried by the Russian side," Ukraine's foreign ministry warned. "To avoid any provocations, we have made all necessary arrangements for safe passage of the convoy. However, despite continued attempts of the Ukrainian side, there still has been no contact established between the general headquarters of the armed forces of Ukraine and Russian Federation, which is critical for safe passage of the convoy. Please note that there is terrorist mortar fire along the possible route of cargo's travel," Ukraine's ministry said.
The U.S. on Aug. 8 said any attempt by Russia to deliver humanitarian aid into Ukraine would be viewed as an invasion.
"Given that Ukraine has allowed international humanitarian groups to deliver aid within its territory, there is no logical reason why Russia should seek to deliver it," U.S. Ambassador to the United Nations, Samantha Power, told a Security Council meeting on Ukraine on Aug. 8, cited by Reuters.
"Therefore, any further unilateral intervention by Russia into Ukrainian territory, including one under the guise of providing humanitarian aid, would be completely unacceptable and deeply alarming. And it would be viewed as an invasion of Ukraine," Power told the 15-member body.
At the same time, Russia’s foreign ministry warned the Ukrainian authorities against any attempts to block the movement of the convoy.
“We are warning against any attempts to sabotage this purely humanitarian mission, which was prepared a long time ago, in the atmosphere of full transparency and in cooperation with the Ukrainian side and the ICRC,” the Russian statement said.
But Ukraine’s office of the Red Cross said Russia has failed to finish the paperwork required for the convoy to be considered part of an international humanitarian mission.
"There is no full inventory [of the aid] and in addition there was never a [safety] guarantee from the separatists that the transport would be allowed to reach the people who need it," said Viktor Sherbanuk, Head of Information Department Ukrainian National Committee of Red Cross.
But the Russian foreign ministry insisted that they “gave all necessary guarantees, provided for such guarantees from the side of the militants – and not only for the Russian column, but for the column with humanitarian cargo sent to Luhansk by the Kyiv authorities.”
The Russian aid convoy consisting of nearly 300 repainted military trucks has been waiting near the Ukrainian border for nearly a week since leaving the Moscow suburbs.
Ukrainian and Russian officials have been attempting to reach a deal that would allow the convoy to be cleared by Ukrainian customs officials on the Russian side of the border before traveling through the rebel controlled checkpoint. Under the deal the ICRC was supposed to handle the transport and distribution of the aid in rebel controlled territory.
Colonel Andriy Lysenko, the spokesman for National Security and Defense Council, said that only 34 trucks had been cleared so far. He said that most of the cleared trucks were loaded only by two-thirds.
Western journalists allowed to examine the trucks stated they were carrying some aid, but were mainly empty. Ukrainian officials have expressed their concern that because of mystery surrounding the purpose of the convoy and its contents, the convoy might be intended to provoke a conflict with Ukraine.
Russian President Vladimir Putin originally said the convoy was planned in conjunction with the Russian Red Cross, but they were never involved in the process.
Editor's Note: This article was updated to include comments made by Ukraine's Foreign Ministry.