(Reuters) - Indian Prime Minister Narendra Modi will meet Chinese President Xi Jinping on Wednesday on the sidelines of the BRICS summit in the Russian city of Kazan, India's foreign secretary said on Tuesday.

India and China share a disputed border that stretches 3,440 km (2,100 miles) and remains poorly defined. Natural features, such as rivers, lakes and snow-covered areas, cause the border to shift at times,

Some of Moscow's key allies have rallied round Russian President Vladimir Putin on the first day of a major summit that the Kremlin hopes will show Western attempts to isolate it over the Ukraine offensive have failed.