KYIV: Ukraine on Thursday ordered the mandatory evacuation of vulnerable residents from the frontline city of Kupiansk and adjacent northeastern territories as fears mount Russia will retake the key city and rail hub.

In September, Russian troops retreated from key cities in the northeastern Kharkiv region, including Kupiansk.

Kupiansk is near the frontline in eastern Ukraine and locals fear it could be taken over again.

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"Mandatory evacuation of families with children and residents with limited mobility began in Kupiansk community," the Kharkiv regional military administration said on its website.

"The decision was made... taking into account the unstable security situation due to constant shelling of the territory of the community by Russian troops," it added.

Kharkiv region governor Oleg Synegubov said Thursday Russia "shelled" several settlements in the region with artillery, multiple rocket launchers and mortars, including the city of Kupiansk.