Russia said on Tuesday that its troops had made major new gains in its western region of Kursk, accelerating their push to drive out Ukrainian forces who have been clinging on to a slice of Russian territory since last August.

A Russian offensive supported by North Korean troops in the past few days has made a serious advance in Russia's Kursk region northeast of Ukraine, breaking through Ukrainian positions and forcing them to withdraw to new defense lines,

By Mark Trevelyan (Reuters) -Ukrainian troops appeared on the point of losing their hard-won foothold inside Russia's Kursk region on Wednesday as Moscow claimed further advances there and military bloggers on both sides said Kyiv's forces were withdrawing.

Russian President Vladimir Putin says the Ukrainian operation is a bid to undermine Russia's stability, slow its advance elsewhere and improve Kyiv's negotiating position. Russia will deliver a "worthy response",