Ukrainian Interior Minister Arseny Avakov told reporters in Kyiv on Thursday that the Russian armored vehicles had been sighted in the border town of Snizhyne.
"We have observed columns passing with armored personnel carriers, other armored vehicles and artillery pieces, and tanks which, according to our information, came across the border and this morning were in Snizhnye," Avakov said.
Avakov said Ukrainian forces had destroyed part of the column and fighting had continued. However, he gave no further details. His assertions could not be immediately confirmed.
Meanwhile, Ukrainian President Petro Poroshenko and his Russian counterpart, Vladimir Putin, used a telephone conversation on Thursday to discuss the ongoing crisis in eastern Ukraine, where pro-Russia separatists have seized control of several cities and towns.
"The president of Ukraine informed Vladimir Putin about his plan to resolve (the problems) in the southeast of Ukraine," the Russian president's spokesman, Dimitry Peskov, was quoted as saying by a number of Russian agencies.
Also on Thursday, Russian Foreign Minister Sergei Lavrov announced plans by the Kremlin to introduce a draft resolution at the United Nations Security Council.
"We have instructed our UN envoy in New York, Vitaly Churkin, to submit a draft resolution to the Security Council on the situation in Ukraine," Lavrov told the state-run Itar-Tass news agency.
"That is because the lack of any progress in the efforts to end the violence ... is causing growing concern," he said.
Lavrov said the draft would not include a provision for Russia to send peacekeeping troops into Ukraine, something that has been requested by pro-Russian separatists in eastern Ukraine.
Ukraine and Western nations have accused Russia of fomenting the unrest in eastern Ukraine, something that the Kremlin has repeatedly denied. A few days ago, President Putin announced that he had ordered stepped-up border controls, amid concerns that both weapons and armed fighters were crossing the border unhindered.
Gas talks break down
Talks between Russia and Ukraine aimed at resolving an ongoing dispute over gas shipments came to an end on Wednesday, with both sides accusing each other of intransigence after they failed to reach an agreement. Russian gas giant Gazprom has now threatened to cut off supplies to Ukraine if it fails to pay off another $1.95 billion (1.44 billion euros) of its gas debts by Monday.
pfd/rc (AFP, AP, Reuters)