U.S. Secretary of State John Kerry on Thursday blamed Russia of making a calculated move to sabotage Ukraine’s elections by beginning military drills near the Ukrainian border, while Russia's ambassador to the U.N. referred to a Kremlin directive that authorizes Russia to use armed forces in Ukraine.

Kerry accused Russia of violating the Geneva deal and said that it would be an “expensive mistake" if Moscow tried to repeat its Crimea tactic, which led to the peninsula's annexation by Russia. Vitaly Churkin, Russia’s ambassador to the U.N., said Friday that Russia is allowed to use armed forces in Ukraine “until the situation normalizes” according to a law signed in the upper house of the Russian parliament on March 1, ITAR TASS, a local news agency reported, adding that Churkin emphasized Moscow's efforts to "de-escalate the conflict."

Kerry said, “If Russia chooses the path of de-escalation... all of us will welcome it. But if Russia does not, the world will make sure that the costs for Russia will only grow,” adding: “It will be an expensive mistake,” according to Reuters.

"Not a single Russian official has publicly gone on television in Ukraine and called on the separatists to support the Geneva agreement, to support the stand-down, to give up their weapons and get out of the Ukrainian buildings," Kerry said, according to BBC, adding: "This is a full-throated effort to actively sabotage the democratic process through gross external intimidation that has been brought inside Ukraine."

Meanwhile, Ukraine´s acting President Oleksandr Turchynov reportedly said that the country will continue to fight pro-Russian separatists in the eastern part of the country, despite Russia beginning military drills near the Ukrainian border. The government said Thursday that five militants had been killed in an offensive launched by the country and later gave Russia 48 hours to explain its military movements.

Russian President Vladimir Putin reacted strongly to Ukrainian military operations, which led to the killing of the protesters, and said, according to the Guardian, “If the Kiev government is using the army against its own people this is clearly a grave crime.”

Ukraine resumed military operations in the eastern part of the country after clashes with pro-Russian separatists led to the killing of a Ukrainian politician and others. 

While Russian Defense Minister Sergei Shoigu claimed Thursday that about 11,000 Ukrainian troops are fighting civilians in southeastern Ukraine, the U.S. and Ukraine maintain that anti-government protesters in eastern Ukraine are, in fact, members of Russian special forces helping Moscow destabilize the country.