Indian Prime Minister Narendra Modi is widely expected to win a third term in power on Tuesday, leading a country with the world's biggest population and fastest-growing economy.

The 73-year-old Hindu nationalist leader, who is pushing for a permanent seat on the UN Security Council, has been courted by the United States and European allies as a counterweight to China.

India, the world's fifth-largest and fastest-growing major economy, is a favourite of Western leaders -- despite warnings by rights activists about rising authoritarianism.

Modi used India's holding of the G20 presidency in 2023 to burnish his image abroad, and hopes to build on hosting the cricket World Cup last year by bidding for the 2036 Summer Olympics.

Here is how a third term for Modi could build on a decade of his diplomatic ambitions.

- United States and Europe -

President Joe Biden hosted Modi for a state dinner last year and has called ties with India the "defining partnership of the 21st century".

In February, Washington approved a $4 billion sale of state-of-the-art drones to India, the latest bolster to India's defence in a counterbalance to neighbouring China.

That deepening of ties has come despite rights groups sounding the alarm about threats to India's democracy and increased discrimination towards the 200-million-plus Muslim minority.

The relationship has not been entirely seamless, however.

The US Justice Department last year charged an Indian citizen with allegedly plotting an assassination attempt in New York approved by India's intelligence agency.

India also has strong ties with European countries.

With France, it hopes to expand multi-billion-dollar deals including the sale of Rafale fighter jets and Scorpene-class submarines.

- China -

Relations between the world's two most populous countries slumped in 2020 after their troops fought a deadly high-altitude skirmish along their 3,500-kilometre (2,200-mile) frontier.

Tens of thousands of troops from the nuclear-armed Asian giants continue to eyeball each other. Territorial claims remain a perennial source of tension.

Modi's right-wing government has pumped billions of dollars into border infrastructure and boosted military spending by 13 percent last year -- but it is still barely a quarter of China's.

Despite their rivalry, China is India's second-largest trade partner.

- Russia -

New Delhi and Moscow have ties dating back to the Cold War and Russia remains by far the biggest arms supplier.

India has shied away from explicit condemnation of Russia for its invasion of Ukraine, abstained on UN resolutions censuring Moscow, and snapped up cut-price Russian crude oil supplies.

Modi in March congratulated President Vladimir Putin on his re-election, adding he was looking forward to developing their "special" relationship.

- Pakistan -

Modi's government has refused to engage with historic rival Pakistan since accusing Islamabad of cross-border terrorism.

The two nations have fought three wars and numerous smaller skirmishes since being carved out of the subcontinent's partition in 1947. Control of contested Kashmir has been at the centre of tensions.

In 2015 Modi made a surprise visit to the Pakistani city of Lahore but relations plummeted in 2019.

But in March, Modi congratulated Pakistani counterpart Shehbaz Sharif on his return to the premiership.

It was a rare expression of goodwill between leaders of the two nuclear-armed rivals, and raised hopes there could be a thawing of relations.

- 'Global South' -

Modi has also projected India as a key member of the BRICS club of emerging economies, and this week called New Delhi "a strong and important voice of the Global South".

It was under Modi's watch that the African Union bloc joined the G20, with India arguing developing nations need a greater say in global decision-making.