NEW DELHI, Oct 21 (Reuters) - India and China have reached a deal on patrolling their disputed frontier to end a four-year military stand-off, the Indian foreign minister said on Monday, paving the way for improved political and business ties between the Asian giants.

The news came on the eve of Indian Prime Minister Narendra Modi's visit to Russia for an Oct. 22-24 summit of the BRICS regional grouping, during which he could hold talks with Chinese President Xi Jinping, Indian officials said.

Relations between the world's two most populous nations - both nuclear powers - have been strained since clashes between their troops on the largely undemarcated frontier in the western Himalayas left 20 Indian and four Chinese soldiers dead in 2020.