The European Union said it was escalating a dispute with Russia at the World Trade Organization over what it said were excessive import duties on paper products, refrigerators and palm oil. The challenge is the latest in a series of WTO disputes with Russia, the EU's third-biggest trading partner, since Moscow joined the body in 2012, although they have been overshadowed by tit-for-tat sanctions triggered by the crisis in Ukraine. "The EU requested today the establishment of a dispute settlement panel at the World Trade Organization in Geneva concerning Russia's excessive import duties, in particular on paper products, refrigerators and palm oil," the European Commission said in a statement. The European Union said it had sought a solution with Moscow in consultations at the WTO in November, but that it had failed to convince Moscow to reduce its 15 percent tariff on paper products. In the case of refrigerators and palm oil, the European Union said Russia sets a minimum sum for its tariff, which is sometimes higher than the agreed duty expressed as a percentage of the product's value. The dispute settlement panel continues a lengthy process that could eventually result in Moscow being fined and told to drop the tariffs, as well as allowing the European Union to adopt counter measures. Trade ties between Brussels and Moscow are already at a low ebb. The EU accuses Moscow of a string of restrictive trade practices including policies to protect the Russian car industry. Meanwhile, Russia banned imports of food from Europe in August, part of its response to EU sanctions imposed over Russia's seizure of Crimea from Ukraine and its backing for pro-Russian rebels. The one-year ban is expected to cost the European Union 5 billion euros ($5.7 billion). (Reuters)