The last time reserves had risen to a comparable level was in the week ended July 25, when it had risen $2.71 billion to $320.56 billion.
Foreign currency assets, a key component of reserves, rose $2.03 billion to $290.37 billion.
Gold reserves fell during the week by $275 million to $19.74 billion.
For the week under review, Special Drawing Rights (SDRs) fell by $19.5 million to $4.27 billion, while the country's reserve position with the International Monetary Fund was down $7 million to $1.54 billion.
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