Il Nuovo Postiglione - India's Modi sworn in as prime minister

Modi's Hindu-nationalist Bharatiya Janata Party (BJP) ruled outright for the past decade but failed to repeat its previous two landslide wins this time around, defying analysts' expectations and exit polls.

He was instead forced into quick-fire talks with the 15-member coalition, the National Democratic Alliance (NDA), which guaranteed him the parliamentary numbers to govern.

Modi, flanked by top BJP officials and party leaders of his coalition, vowed in a ceremony marking his formal assumption of power to "bear true allegiance to the constitution of India".

Honour guards lined the steps of the presidential palace where thousands gathered to watch Modi, dressed in a white kurta and with blue waistcoat, take the oath.

South Asian leaders from neighbouring Bangladesh, the Maldives and Sri Lanka attended the ceremony but neighbouring rivals China and Pakistan had notably not sent top leaders.

- Bollywood and business tycoons -

The cheering crowd also included adoring BJP loyalists, as well as celebrities such as Bollywood legend Shahrukh Khan and billionaire tycoons Gautam Adani and Mukesh Ambani, key Modi allies.

But with Modi yet to announce his new cabinet, the line of lawmakers also taking the oath of office was keenly watched as an indication of who will be in government.

Modi was followed immediately by top BJP aides Rajnath Singh, Amit Shah and Nitin Gadkari -- the defence, interior and transport ministers in his last government respectively.

Tenth to take the oath, and first among the BJP's coalition members, was H.D. Kumaraswamy from the Janata Dal (Secular) party.

Larger coalition parties have demanded hefty concessions in exchange for their support.

Other coalition leaders to take the oath included Ram Mohan Naidu of the Telugu Desam Party (TDP), the largest BJP ally with 16 seats, and which India media reports has extracted four cabinet positions.

Rajiv Ranjan Singh also took the oath, from the BJP's next biggest ally the Janata Dal (United) with 12 seats, which has reportedly two minister posts.

Modi described recent days as "very busy" in an article published on his website Sunday ahead of the ceremony, saying he was in the "midst of preparations of government formation".

Indian media reported widely that the top jobs including the four most powerful posts of the interior, foreign, finance and defence would remain in the BJP's grip.

The Hindustan Times described days of "hectic talks", while the Times of India said the BJP had sought to "pare down" their partners' demands.

Modi's previous cabinet had 81 ministers.

- 'More consultation' -

But analysts said that the coalition will shift parliamentary politics and force Modi's once domineering BJP into a somewhat more conciliatory approach.

"In the past, the BJP has had confidence because of its sheer majority," said Sajjan Kumar, head of the Delhi-based political research group PRACCIS.

"The coalition will now force the BJP to engage in more consultation."

Political analyst Zoya Hasan of Jawaharlal Nehru University told AFP that Modi faced potential challenges ahead -- warning he may be "meeting his match" in the "crafty politicians" of the TDP's Chandrababu Naidu and JD(U)'s Nitish Kumar.

Modi's chief rival Rahul Gandhi was nominated on Saturday to lead India's opposition in parliament, after he defied analysts' forecasts to help the Congress party nearly double its parliamentary numbers.

It was Congress's best result since Modi was swept to power a decade ago, rescuing the party from the political wilderness.

Gandhi is the scion of the dynasty that dominated Indian politics for decades and is the son, grandson and great-grandson of former prime ministers, beginning with independence leader Jawaharlal Nehru.

If elected, as expected, he will be recognised as India's official opposition leader when the new parliament sits, which local media reports suggest will happen as early next week.

M.Dodaro--INP