(QHA) -

Ukraine says its forces, backed by warplanes, have broken a rebel blockade of Luhansk airport in eastern Ukraine.

Ukraine's military said the air strikes inflicted heavy losses on the pro-Russian separatists, including an armored convoy that Kyiv says crossed the border from Russia.

Ukrainian President Petro Poroshenko's office said Kyiv will present proof of incursions from Russia to the international community on July 14.

Meanwhile, the Russian daily "Kommersant" quoted a source close to the Kremlin as saying Moscow was considering the possibility of "targeted retaliatory strikes" against Ukraine over cross-border shelling hitting Russian territory.

Moscow said on July 13 that a Ukrainian shell had killed a civilian in the Russian border town of Donetsk. 

Ukraine denied the claim, saying government forces "never will fire on the territory of a neighboring state."