FRANKFURT, March 15 - Ukraine's president accused Russian-backed separatists in the east of failing to respect a ceasefire with Ukrainian troops and called for further sanctions on Russia in comments to a German newspaper to be published on Monday, Reuters reported.

Attacks have become less frequent since the latest ceasefire came into force in mid-February, but both sides accuse each other of violations. Ukraine's military said last week that pro-Russian rebels were using the truce to amass heavy weapons.