"The two crore families of Delhi have now said that their son Arvind Kejriwal
is not a terrorist but a staunch nationalist. I salute the people of Delhi from (for) giving AAP such a massive mandate," Singh said in a tweet.
The AAP leader was referring to remarks made by BJP MP Parvesh Verma at a poll rally. Verma had called Kejriwal a "terrorist" over his alleged support to an anti-Citizenship (Amendment) Act protest in south Delhi's Shaheen Bagh.
"Despite BJP leaders putting all their force behind it (election campaign), the son of Delhi won. Amit Shah
has been shown that the son of Delhi has won and people of Delhi have voted for development and progress," said Singh, referring to Kejriwal.
Singh was addressing party workers at the AAP headquarters here.
According to EC's website, Kejriwal was leading from his New Delhi constituency. He reached the party office as the counting got underway.
Counting centres are spread across 21 locations, spanning 70 constituencies.
Polling for the 70-member Delhi Assembly was held on Saturday.