India's powerful Nehru-Gandhi dynasty launched a blistering attack on Tuesday on Narendra Modi, as the opposition Congress party began election campaigning with a massive rally in the prime minister's home state.

Rahul and Priyanka Gandhi, the sibling descendants of India's founding leader Jawaharlal Nehru, likened their quest to defeat Modi to the country's pre-independence struggle against British rule.

The pair — Rahul as Congress leader and his sister Priyanka, who is spearheading campaign efforts in a must-win state — rallied side-by-side for the first time since the national election was announced at the weekend.

Some Congress supporters see a likeness between Priyanka and her powerful grandmother Indira Gandhi, India's first female prime minister, and are banking on “Priyanka magic” to win votes.

“Leaders who made big promises in 2014 should be asked, where is that which they promised?” Priyanka told a huge Congress rally in Gujarat, a stronghold state ruled for 12 years by Modi as chief minister before his ascension to top office.

Rahul Gandhi has been attacking Modi over his economic record, accusing him of failing on his election promise in 2014 to create employment for India's millions of job seekers.

Critics say Modi's flagship policies — including new taxes and the cancellation of huge numbers of banknotes — have not produced promised jobs, while India's farmers are up in arms over massive debt burdens.

But analysts say the BJP has gained ground after India launched air strikes within Pakistani territory last month after a suicide bombing that killed 40 Indian paramilitary troops in occupied Kashmir.

Congress has sought to deflate the BJP's advantage over the clash with Pakistan, questioning the potency of the strikes.