(Reuters) - EU leaders will meet for a special summit in Brussels on Thursday to discuss the bloc's further response to Moscow after Russian President Vladimir Putin ordered troops into breakaway regions of eastern Ukraine.

       "It is important that we continue to be united and determined and jointly define our collective approach and actions," the head of the EU Council grouping the bloc's member states, Charles Michel, said in a statement on Wednesday.

       (Reporting by Sabine Siebold and Marine Strauss)