Several top leaders, spokespersons and union ministers came in. BJP president Amit Shah would arrive by 1 pm, reporters were told.
Cutouts of Prime Minister Narendra Modi and Amit Shah were held up at the BJP office in Bengaluru by slogan-shouting workers.
In less than three hours of counting, the BJP had crossed the half-way mark and was on its way to winning a majority on its own - without any support.
"There is no question of alliance with the Janata Dal Secular as we are already crossing 112 seats," said BJP leader Sadananda Gowda.
Shobha Karandlaje, a close aide of the BJP's presumptive chief minister BS Yeddyurappa, said: "We have achieved our dream of Congress-mukt Karnataka and Amit Shah, Modi, Yeddyurappa here."
It gives PM Modi and his party far more confidence as India prepares for national elections next year. The party had been seen to tackle a rough patch in the aftermath of recent by-election losses in Rajasthan and Uttar Pradesh; the opposition seized on the defeats, saying the ruling party was facing public anger because of rural distress and poor job creation,"
Barbs flew freely from the BJP camp.
"This is a historic win for BJP. I want to thank all the people of Karnataka for voting for us. Ab desh mein Congress khojo abhiyan chalega, kahaan rahegi pata nahi (There will now be a Congress khojo (look for Congress) drive," said Raman Singh, Chhattisgarh Chief Minister.
Get Breaking news, live coverage, and Latest News from India and around the world on NDTV.com. Catch all the Live TV action on NDTV 24x7 and NDTV India. Like us on Facebook or follow us on Twitter and Instagram for latest news and live news updates.