The Reserve Bank of India today said, country's foreign exchange reserves rose sharply by 3 billion dollars to touch a new life-time high of 417.789 billion dollars in the week to January 26, aided by a rise in foreign currency assets. In the previous week, the reserves had increased by 959.1 million dollars to 414.784 billion dollars.The reserves had crossed the USD 400-billion mark for the first time in the week to September 8, 2017 but has since been fluctuating. But for the past four weeks, it has been on a continuous rally.Expressed in US dollar terms, the foreign currency assets include the effect of appreciation or depreciation of the non-US currencies such as the euro, the pound and the yen held in the reserves.The central bank said, gold reserves remained unchanged at 20.421 billion dollars.