Russian Convoy
Trucks of a Russian convoy carrying humanitarian aid for Ukraine are parked on the roadside as they drive towards the Ukrainian border near Donetsk located in Rostov Region, August 21, 2014. Ukrainian border guards began on Thursday to inspect a Russian truck convoy carrying aid earmarked for humanitarian relief in eastern Ukraine that has been stranded at the frontier between the two former Soviet republics for nearly a week. Reuters

NATO, the Pentagon and Ukrainian officials have condemned a purported Russian aid convoy's entrance into Ukraine. Part of the convoy, which Russian officials describe as humanitarian in nature, headed toward rebel-held eastern Ukraine without the approval of authorities in Kiev or the participation of the Red Cross.

“This is a blatant breach of Russia’s international commitments, including those made recently in Berlin and Geneva, and a further violation of Ukraine’s sovereignty by Russia. It can only deepen the crisis in the region, which Russia itself has created and has continued to fuel,” NATO Secretary General Anders Fogh Rasmussen said in a statement Friday. “The disregard of international humanitarian principles raises further questions about whether the true purpose of the aid convoy is to support civilians or to resupply armed separatists.”

Rasmussen’s statement marked the first time that NATO has directly accused Russia of providing artillery support to pro-Russian separatists within Ukrainian territory, said the Washington Post. “These developments are even more worrying as they coincide with a major escalation in Russian military involvement in Eastern Ukraine since mid-August, including the use of Russian forces. In addition, Russian artillery support -- both cross-border and from within Ukraine -- is being employed against the Ukrainian armed forces,” he said.

Pentagon spokesman Rear Adm. John Kirby denounced Russia’s “unauthorized entry” into Ukraine. “We strongly condemn this action and any actions that Russian forces take that increase tensions in the region. Russia should not send vehicles, persons or cargo of any kind into Ukraine, whether under the guise of humanitarian convoys or any other pretext, without Kiev’s express permission,” Kirby told reporters.

Ukrainian President Petro Poroshenko said "a column of more than 100 vehicles entered Ukrainian territory without a customs inspection, without border control or International Red Cross escort, which is a flagrant violation of international law.” Security chief Valentyn Nalyvaychenko said that Ukraine would not take action against the convoy in order to avoid “provocations,” amid the Russian foreign ministry’s vague warnings of reprisal, the BBC reports. However, Ukraine has not ruled out the possibility of military action if evidence suggests that the convoy has aided local rebels.

Customs officials at the Ukrainian border inspected and approved a portion of the convoy under the assumption that the Red Cross would be present, CNN reports. Instead, the Red Cross announced that it would not participate in the convoy due to a “volatile security situation.”

Russia has denied allegations that it has armed or supported rebels in Ukraine. However, a U.S. defense official told CNN that Russia currently has as many as 18,000 “combat-ready” troops on the Ukrainian border.