"According to widespread information, the Ukrainian Foreign Ministry recently hosted a meeting of the country's law enforcement bodies to discuss measures to toughen control over the presence of Russia's Black Sea Fleet on the territory of Ukraine," Foreign Ministry spokesman Andrei Nesterenko said.
"It puts us on our guard that such a conference occurred against a backdrop of reports confirmed by Ukrainian officials that various plans are being developed in Ukraine to organize provocations in Crimea to destabilize the situation on the peninsula and surrounding the Black Sea Fleet," Nesterenko said at a press conference.
He said it was strange that the Ukrainian Foreign Ministry had not refuted the reports.
"We call on the Ukrainian side to accept complete responsibility for the possible catastrophic consequences for Russian-Ukrainian relations such provocations could cause," Nesterenko said.
Under bilateral agreements, Russia's Black Sea Fleet has the use of the Sevastopol base until 2017. Ukrainian President Viktor Yushchenko recently announced that Ukraine would not extend the lease beyond the date.