Brussels: Russia has moved troops closer to the border with Ukraine and continues to support rebels in the country's east, NATO's chief said on Tuesday, after an election held by the pro-Russian separatists and condemned by Kiev and Western leaders.

Ukraine's president said Sunday's vote flouted terms of a plan to end a war that has killed more than 4000 people, and that newly formed army units would be sent to defend a string of eastern cities against a possible new rebel offensive.

EU weighing more sanctions: European Union foreign policy chief Federica Mogherini. Credit:Reuters

"Recently we are seeing Russian troops moving closer to the border with Ukraine," Jens Stoltenberg, secretary-general of NATO, told a news conference with EU foreign policy chief Federica Mogherini.

"Russia continues to support separatists by training them, by providing equipment and support them by also having Russian special forces inside eastern parts of Ukraine."