"It is despicable and barbaric," Menon said while commenting on the arrest of Khobragade in New York on charges of violating visa rules.
The strong comments by the NSA came as Indian leaders, including Congress Vice President Rahul Gandhi and Home Minister Sushilkumar Shinde, refused to meet a US Congressional delegation as a mark of protest over the treatment meted out to 39-year-old Khobragade.
Menon himself did not meet the delegation on Monday.
Lok Sabha Speaker Meira Kumar had also cancelled her meeting with the delegation on Monday.
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