The assembled for the Leaders’ Summit on Peacekeeping hosted by US president Barack Obama, Modi walked into the conference hall first. Sharif followed a few minutes later and waved at Modi. The Indian PM waved back and smiled.
Then there was a pause, after which Modi waved again and Sharif acknowledged and smiled.
The two leaders, who are in New York for UN summits, came across each other for the first time on Monday.
At the conference, they were seated across the horse-shoe-shaped table.
Ahead of the UN meet, there were questions whether the two leaders will have a meeting or at least manage a handshake, particularly since they are staying in the same hotel.
Modi and Sharif had last met in Ufa, Russia, in July on the sidelines of the BRICS and SCO summits.