Aam Aadmi Party leader Ashutosh said: "It's BJP/Modi who ha(ve) been opposing talks with Pakistan during the time of (former prime minister) Manmohan Singh under the pretext of Pakistan-sponsored terrorism. What has changed now?
"We have always been saying (that) engagement with Pakistan is needed but BJP was opposing. Now they should explain - why so much friendship?" he said in tweets.
He asked whether Pakistan-backed terrorism had stopped as Pakistani Prime Minister Nawaz Sharif had now become a likeable figure to Modi.
Modi flew into Lahore on Friday and met Sharif while returning home from Kabul. He also wished Sharif on his birthday. Friday also marks the 139th birth anniversary of Muhammad Ali Jinnah.