Russia and Ukraine signed on Wednesday a protocol regulating the presence of Russian security officers at the Black Sea Fleet facilities in Ukraine, the Ukrainian Security Service (SBU) said.
"The protocol stipulates the exchange of information and coordinated efforts to prevent illegal activities against Russia's Black Sea Fleet that pose a threat to the national security of Ukraine and Russia," the SBU said in a statement.
The protocol became effective on the day of the signing and will be in force for the next five years.
The sides also discussed on Wednesday bilateral cooperation in the fight against global terrorism, drug-trafficking, and illegal immigration.
Ukraine ordered 19 Russia's Federal Security Service (FSB) officers to leave Crimea's Sevastopol, where Russia's Black Sea fleet is based, late last year.
However, victory in February's presidential elections for "pro-Russian" candidate Viktor Yanukovych has led to a dramatic improvement in bilateral ties, which soured under the previous president, Viktor Yushchenko.
Yushchenko had pledged to force the Russian fleet to leave Crimea when its lease expired in 2017. But, under a deal finalized last month, Ukraine agreed to prolong the lease for 25 years in exchange for a 30% discount on Russian natural gas.
A source in Sevastopol's security structures earlier said the first group of Russian security officers has already returned to the base and begun preparing for joint anti-terrorism drills with their Ukrainian counterparts.
KIEV, May 20 (RIA Novosti)