Ukraine said on Wednesday it wanted to discuss charging Russia more for the lease of a Black Sea naval base, a move that could aggravate regional tensions already enflamed by Moscow's conflict with Georgia. Ukrainian President Viktor Yushchenko said Kiev wanted to raise the question of increasing Russia's rent on its Sevastopol base in Ukraine's Crimea region, the headquarters of the Russian Black Sea fleet. Russia has said any renegotiation would break a 1997 agreement between the two countries, under which it currently leases the base for $98 million a year until 2017. British Foreign Secretary David Miliband called on Russia to change course Wednesday but acknowledged that Western attempts to isolate Moscow over its actions in Georgia would be counterproductive. On a visit to Ukraine, Miliband urged Kiev “not to provide any pretext” for Russia to take action against the former Soviet republic, which has sided with Georgia in its confrontation with Moscow. Miliband said isolating Russia would be “counterproductive,” arguing that the West relied on cooperation with Moscow to tackle global problems like climate change and nuclear non-proliferation. “Isolation is not feasible – Russia is too enmeshed in the world economy. It would be counter-productive,” he said. “Russia has not reconciled itself to the new map of this new region...We do not want a new Cold War and he (Medvedev) has a big responsibility not to start one,” Miliband told a group of students. As the US Navy shipped in humanitarian supplies to Georgia, Russia said its navy was watching "the build-up of NATO forces in the Black Sea area" and had started taking measures to monitor their activity. Georgia recalled all but two of its diplomats from Moscow in protest after Russia recognised its rebel South Ossetia and Abkhazia regions as independent and President Mikheil Saakashvili urged the West to uphold international law. "Russia clearly intended this as a blatant challenge to world order. It's now up to all of us to roll Russian aggression back. If they get away with this, they will carry on ... they will also attack other countries in the neighbourhood," Saakashvili told Reuters. Russia quickly crushed Georgian forces in a brief war over South Ossetia this month, the first time it has sent its forces into combat abroad since the 1991 collapse of the Soviet Union. Russian troops and tanks continue to occupy parts of Georgia included in buffer zones it set up around South Ossetia and Abkhazia, and has ignored Western demands to withdraw from them. It says its troops are needed there to protect civilians. German Chancellor Angela Merkel told Kremlin leader Dmitry Medvedev Russia's presence in Georgia's port of Poti and other areas outside Abkhazia and South Ossetia "represents a grave violation" of a ceasefire, her spokesman said. US President George W. Bush said recognition of the rebel regions by Russia "only exacerbates tensions and complicates diplomatic negotiations."