Moscow planned move against Ukraine before protests , Ukraine 's President says . Russia has been sending troops into eastern Ukraine to support pro-Russian rebels fighting the government in Kiev since mid-February. Continued violence mars a ceasefire deal intended to end the conflict .
Moscow planned move against Ukraine before protests , Ukraine 's President says . German leader says implementing a ceasefire is not easy but is still the best chance for peace . Continued violence mars a ceasefire deal intended to end the conflict .