A senior leader of India's main opposition Congress party, Manmohan Singh, has announced a regional alliance with the main opposition party in the southern state of Tamil Nadu, the Dravida Munnetra Kazakham (DMK).
Mr Singh said the two parties had decided to come together to fight the upcoming national elections.
He said the DMK would lead the alliance in the state.
Correspondents say Congress is now open to forming regional alliances, following its poor performance in recent state elections.
The Dravida Munnetra Kazakham recently broke its alliance with the central coalition government led by the Hindu nationalist BJP.
From the newsroom of the BBC World Service