NEW DELHI — India's ruling Congress party, which has been battered by corruption scandals, won a much-needed victory Wednesday in an election in a key southern state. The party wrested power from the Hindu nationalist Bharatiya Janata Party in Karnataka. The voting was watched as a possible bellwether for next year's national elections. The election commission said the Congress party had achieved a majority with 118 seats and was leading in three other of the state's 224 constituencies as of Wednesday evening. The BJP had won or was leading in only 40 constituencies, with the rest going to other parties. Prime Minister Manmohan Singh hailed his party's victory but acknowledged that corruption was an important issue. “We must sit together and find a solution,” the Press Trust of India news agency quoted him as saying. Salman Khurshid, a top Congress leader and India's external affairs minister, said the outcome “has given us a great shot in the arm.” Karnataka's capital, Bangalore, is the country's information technology hub. Chandan Mitra, a BJP lawmaker, said Karnataka voters had punished his party for its poor governance in the state. However, he warned Congress that it would badly lose next year's national elections because “it is sitting on a corruption keg.” Several top Congress officials are facing corruption allegations stemming from scandals over the hosting of the 2010 Commonwealth Games, the irregular sale of cellphone spectrum and the allocation of coal fields that auditors said cost the country billions of dollars. The BJP in Karnataka had scandals of its own. Although the party came to power in the state only five years ago, its lawmakers quickly became embroiled in an alleged multibillion-dollar scam involving the granting of illegal mining contracts. The lawmakers, along with hundreds of government officials, are being prosecuted on bribery charges. The defeat of the BJP in Karnataka deprived India's main opposition party of its only stronghold in southern India, but analysts said the Congress victory was based not on its strength, but on the weakness of its opponents. “The Congress party benefited through default,” said Vinod Mehta, a political analyst. The BJP's vote share was also reduced by a split in the state party, said Rajiv Pratap Rudy, a BJP spokesman. — AP