Russian President Vladimir Putin has lashed out Ukraine, accusing the government of "terror" after the Federal Security Service (FSB) claimed that Kyiv tried to send saboteurs into Crimea and that a soldier and an FSB officer were killed thwarting the alleged armed raids.
Ukrainian President Petro Poroshenko rejected the Russian claims, which followed an increase in Russian military activity in the northern part of Crimea near the border with mainland Ukraine, as "fantasies" and "provocation."
The Russian claims added to tension between Moscow and Kyiv, already on the rise following an upsurge in fighting in the conflict between Ukrainian government forces and Russia-backed separatists in eastern Ukraine.
"This is very alarming news," Putin said on August 10. "In fact, our security services prevented an incursion into the territory by a sabotage-reconnaissance group from Ukraine's Defense Ministry."
Putin said Kyiv's alleged actions were "stupid" and "criminal" and that there was no point in holding talks on the foundering peace process in eastern Ukraine -- a reference to proposals for a meeting between Russia, Ukraine, Germany, and France on the sidelines of a Group of 20 summit on September 4-5 in China.
He said the alleged infiltration attempt showed that the Ukrainian government had "turned to the practice of terror instead of searching for compromises, instead of searching for pathways to a peaceful settlement," and suggested Russia would seek revenge for the two deaths, which the FSB said occurred in clashes over the weekend.
"From the Russian side there were losses -- two soldiers killed. We obviously will not let such things slide by," Putin said. He said Russia would take "serious" measures to ensure security in Crimea.
The FSB said it believed Ukrainian special forces had been planning attacks targeting critical infrastructure.
"The aim of this subversive activity and terrorist acts was to destabilize the sociopolitical situation in the region ahead of preparations and the holding of elections," the FSB said, referring to Russia-wide parliamentary elections next month.
Kyiv: 'Fake Information'
A spokesman for Ukrainian military intelligence denied the accusations. "This is fake information," the spokesman said.
"Russian accusations toward Ukraine of terrorism in the occupied Crimea sound as preposterous and cynical as the statements of the Russian leadership about the absence of the Russian troops in [eastern Ukraine]," President Poroshenko said.
"These fantasies are only a pretext for more military threats against Ukraine."
Poroshenko also said Moscow would not succeed in getting international sanctions on Russia lifted by trying to discredit Ukraine.
The Ukrainian Defense Ministry said the FSB's assertions looked like an attempt to justify "acts of aggression" and the redeployment of military units to Crimea, which Russia seized from Ukraine in March 2014 after deploying troops and staging a referendum denounced by most of the world as illegitimate.
"Representatives of the Russian special services are trying to divert the attention of the local population and the international community from criminal acts to transform the peninsula into an isolated military base," the Defense Ministry said in a statement.
After taking over Crimea following the downfall of a Moscow-backed Ukrainian president who was driven from power by protesters in Kyiv in February 2014, Russia threw its support behind separatists who seized territory in the eastern Donetsk and Luhansk regions, leading to a war that has killed more than 9,500 people since that April.
Russian Escalation Imminent?
The Russian allegations, and Putin's stern warning, appeared to rekindle suspicions in Kyiv that the Kremlin wants to take control of more territory in Ukraine.
"Putin wants more war. Russia escalates, desperately looks for casus belli against Ukraine, tests [the] West's reaction," a spokesman for Ukraine's Foreign Ministry, Dmytro Kuleba, wrote on Twitter.
In 2014, Russia justified its seizure of Crimea with claims that the residents of the peninsula were in imminent danger from the new, pro-Western government that came to power when President Viktor Yanukovich was forced out and fled to Russia. Kyiv and the West say there are no grounds for that claim.
In its statement on August 10, the FSB said that it confronted one group of Ukrainian saboteurs in an operation late on August 7 and early on August 8, breaking up what it claimed was a Ukrainian spy network.
The FSB said that Ukrainian and Russian citizens were arrested and an arms cache -- including 20 homemade explosive devices, ammunition, mines, and grenades -- had been recovered. It said the situation escalated late on August 8 and in the early hours of August 9.
"Ukrainian special-forces units tried to break through two more times with groups of saboteur-terrorists but were thwarted by FSB units and other forces," it said. "The attempts to break through were accompanied by massive covering fire from the neighboring state and from Ukrainian armored vehicles."
Tensions were high in the northern part of Crimea over the weekend, with residents reporting sightings of long convoys of heavy Russian weaponry not far from the Black Sea peninsula's border with mainland Ukraine.
Crimean Tatar activists had reported armed checkpoints being erected at scattered sites around the Russian-occupied peninsula, and unusually large concentrations of Russian hardware in northern regions.
The crossing from the mainland to the Russian-annexed peninsula was shut for several hours on August 7, causing long backups of traffic.
Photos and videos posted on the website of the Crimean Human Rights Group, a local nongovernmental organization, showed Russian military trucks being transported on trains on August 6 near Kerch, an eastern port town that is opposite Russia's Stavropol territory.
The takeover of Crimea and interference in eastern Ukraine, where Kyiv and NATO say Moscow has sent large numbers of troops and weapons during the war, has severely damaged Russia's ties with its mostly Slavic, Orthodox Christian neighbor and brought tension between the Kremlin and the West to levels not seen since the Cold War.
With reporting by Reuters, AP, AFP, TASS, and Interfax