Describing the BJP's win in 104 seats in Karnataka as a good sign of its expansion in South India, BJP chief Amit Shah on Saturday said that it is a "very potential region" for his party's expansion.

This is an indication that the saffron party will make a serious bid to deepen its imprint in the region as it confronts formidable Opposition alliances in the northern states now.

Addressing a press conference at which he claimed that the BJP's return to power in 2019 is "not a challenge but a certainty", he dismissed any challenge from Rahul Gandhi to a "most hardworking Modi".

He ducked questions on his strategy, particularly for Tamil Nadu, where power has been alternating for three decades between the DMK and AIADMK and merely said that he cannot disclose the strategy to media.

"South India is a very potential region from the point of view of BJP's expansion. Winning 104 seats in Karnataka is a good sign but how can we disclose the strategy?" he said as he expressed confidence about the general elections.

On Rahul Gandhi's remarks in the run-up to the Karnataka Assembly polls that he may be prime minister if his party gets required numbers, Shah said no one in his party or among allies endorsed the idea.

Projecting the Modi dispensation as "policy-driven", he accused the Opposition parties of "peddling lies", which he said would continue as a strategy till the general elections.

Shah's assertions regarding the BJP's expansion plans in South India have come even as there is a view in the Opposition camp that the ruling party's South India gambit could well have come to nought after its failure to form a government in Karnataka, which it planned to use as a gateway to South India.