The sanctions, imposed over the Ukraine crisis, are designed to block access to Western credit and technology for people and businesses linked to President Putin. Combined with American and Group of Seven sanctions, they have made it harder for Russia to weather an economic crisis fuelled by low oil prices.
The EU earlier this month extended economic sanctions on Russia until the start of 2017, despite misgivings from some countries such as Slovakia who are keen to debate their effectiveness.
Several Moscow-based EU diplomats say Russia's tactic of methodically lobbying southern and eastern EU member states is starting to seriously erode the bloc's unity on the issue, making it potentially harder to renew them next time.
"Russia is constantly trying to find a way around the sanctions, targeting countries it thinks are softer. They are trying to kill the sanctions with a softly softly approach," one of the diplomats, from a country which favours their continuation, told Reuters.
"The result is that we are seeing more and more countries saying we should analyse the sanctions, assess what effect they are having, and review them again."
Italy, Greece, Hungary, Cyprus, Slovenia, Slovakia and Bulgaria were among Moscow's prime targets, diplomats said.
Slovenia, where Putin will preside over a summit focused on trade and investment, will be the fourth of those countries he has visited since Russia annexed Crimea from Ukraine in 2014 and a pro-Russian separatist revolt broke out in eastern Ukraine.
The Kremlin sees Slovenia, which Putin has visited before, as an ally in its sanctions quest. Russia was a big export market for Slovenian food products before the Ukraine crisis and Slovenia remains keen to be a transit country for a potential pipeline carrying Russia gas to southern Europe.
Some EU members, such as Poland, have angered Moscow by tearing down monuments commemorating Soviet soldiers killed during World War Two. Slovenia is taking the opposite approach and the Kremlin said Putin would attend the unveiling of a new monument to Soviet soldiers in Ljubljana.
Reuters
