The JD(S) said Tuesday that it was doing "doing everything to keep BJP out of power" in Karnataka after the Congress offered it support to form a government in the state.
"Congress has extended its support, we have accepted it. We will jointly go to meet governor after 5.30 pm today," ANI quoted JD(S) spokesman Danish Ali as saying.
The Congress' Ghulam Nabi Azad had announced earlier on Tuesday that his party had offeredsupport to the JD(S).
"We had a telephonic conversation with Deve Gowda jiand Kumaraswamy. They have accepted our offer. Hopefully, we will be together," Azad said.
Karnataka has a total of 224 assembly seats, but only 222 seats went to the polls this election. (Voting was postponed in two seats.)
The halfway mark then is 112 seats.
Official EC trends at the moment say the BJP has won or is leading in 104 seats, the Congress in 78, the JD(S)+ in 37, and Others 3.
That would give the JD(S)-Congress a total of 115 seats.
News reports had said earlier that former Congress President Sonia Gandhi had spokenwith Ghulam Nabi Azad, who then spoke with JD(S) leader HD Deve Gowda and his son HD Kumaraswamy.
Azad said he had told Gowda and Kumaraswamy that the picking of a chief minister would be left to them.
Should the JD(S) accept the Congress' offer, it is expected that Kumaraswamy will take the CM's post.
The Congress' KC Venugopal meanwhile said the JD(S) and Congress would together meet the governor in the evening today to stake their claim to forming a government in the state.
What happens next will dependon the governor, Vajubhai Vala. Vala was appointed by the Modi government four years ago.
News reports Tuesday meanwhile said the BJP too had reached out to Deve Gowda.