BJP had earlier invited officials from Indian missions of various countries to a rally in the national capital before the Delhi elections.
Khobragade was arrested in New York last week on the charge of visa fraud and subjected to strip search.
BJP has been unhappy with the US decision not to extend a visa to Modi due to his alleged involvement in the Gujarat riots of 2002.
Its leaders had raised this issue on several occasions in the past and insisted an elected leader like Modi cannot be denied a visa when no charges have been proved against him.