Russia claimed Sunday that its forces are for the first time pushing into the central Ukrainian region of Dnipropetrovsk, an area it has been trying to reach for months, in a move that could create new problems for Kyiv’s much-stretched forces.

Amid the stall in the prisoner swap deal, Ukraine has rejected Russia’s claim that its troops have crossed into the Dnipropetrovsk region as “disinformation."

By Guy Faulconbridge and Lidia Kelly MOSCOW (Reuters) -Russian forces on Wednesday advanced further into Ukraine's northern region of Sumy, threatening the regional capital after taking more than 150 square km (58 sq miles) of the area in less than two weeks,