Opposition BJP and Congress Saturday condemned slapping of Delhi Chief Minister Arvind Kejriwal by a man during a roadshow here, but expressed "doubts" that the incident may be a handiwork of AAP to gain sympathy of voters before the Lok Sabha polls in the city.

Delhi Congress spokesperson Jitender Kochar alleged that the incident was stage-managed by Kejriwal for gaining sympathy of Delhiites.

"The incident is as an old move of Kejriwal to  stage-manage attacks on him and then seek public sympathy. But people of Delhi will not succumb to this political manoeuvre by him," he said.

The chief minister was slapped by the man during his roadshow in Moti Nagar in the New Delhi constituency, prompting a strong reaction from the AAP which alleged BJP was behind the "cowardly act".

Police said the man has been taken into custody and an investigation into the matter was underway.

Condemning the incident, Delhi BJP president Manoj Tiwari said his party does not support violence.

"But I have doubts as to why such incidents happen with Kejriwal in election time only. I doubt this incident may have been scripted by Kejriwal himself," he said.

Kejriwal was on an open jeep when the man wearing a red T-shirt jumped onto the vehicle and slapped him.

DCP (West) Monika Bhardwaj said the man has been identified as Suresh, 33, and he deals in spare parts in Kailash Park area.

Delhi Deputy Chief Minister Manish Sisodia slammed the BJP after the incident.

"Do Modi and Amit Shah want Kejriwal to be murdered?" he tweeted.

The AAP leader said the BJP could not break the morale of Kejriwal and not defeat him in elections in five years despite putting in all its might.

"Now you want him removed from your way like this. You cowards! This Kejriwal is your end," he said in a tweet in Hindi.

This is the second time Kejriwal has been slapped in a public rally. He had also been attacked with ink and spices earlier.