EU influence in the former Soviet Union is a sensitive issue and will be put to the test at an EU "Eastern Partnership" summit opening in Vilnius, Lithuania.
Ukraine froze a far-reaching co-operation deal with the EU last week, triggering mass pro-EU rallies in its cities. The BBC's Chris Morris examines the EU's geopolitical tussle with Russia.
They still stand watch at the Green Bridge over the Neris River in the centre of Vilnius.
