LVIV, Ukraine (Reuters) -Ukrainian Foreign Minister Dmytro Kuleba said on Friday peace negotiations with Russia were difficult, and denied reports that progress had been made in resolving four out of six key issues. “There is no consensus with Russia on the four points,” Kuleba said in a post on Facebook. “The negotiation process is very difficult. The Ukrainian delegation has taken a strong position and does not relinquish its demands. We insist, first of all, on a ceasefire, security guarantees and territorial integrity of Ukraine.” Kuleba later tweeted that there was “no consensus in negoti…