Bihar Chief Minister Nitish Kumar on Saturday congratulated the Congress, his alliance partner, for its scintillating performance in the Karnataka assembly polls.

The JD(U) supreme leader came out with a tweet, in Hindi, tagging the grand old party which has won a comfortable majority in the southern state.

"Heartiest congratulations and good wishes to the Congress upon its victory, with a clear majority, in Karnataka assembly elections," Kumar tweeted.

Helped by a nearly five per cent vote swing in its favour, the Congress with a vote share of 42.88 per cent bagged 135, out of the 224 seats in Karnataka, and was leading in one, according to Election Commission data at 10 pm.

The BJP won 65 seats, a sharp drop from its tally of 104 in 2018.

Kumar has vowed to oust the saffron party from power at the Centre by uniting the opposition across the country.