Protests have erupted in India's capital New Delhi over a new citizenship law that has been the centre of violent clashes in recent months, as thousands anticipate the arrival of US President Donald Trump.

Key points: The law offers a path to Indian citizenship for religious minorities in neighbouring countries, but excludes Muslims

The law offers a path to Indian citizenship for religious minorities in neighbouring countries, but excludes Muslims Mr Trump will raise the issue of religious freedom in the country with the Indian Prime Minister Narendra Modi

Mr Trump will raise the issue of religious freedom in the country with the Indian Prime Minister Narendra Modi Hundreds of thousands of people are expected to gather to greet Mr Trump at a rally before a summit with Indian officials in New Delhi

The latest clashes between thousands of protesters and police turned violent ahead of Mr Trump's arrival on Monday, after a week of demonstrations opposing the citizenship law — which would ease the path for non-Muslims from neighbouring Muslim-majority nations to gain citizenship.

The law has sparked months of unrest against Prime Minister Narendra Modi's Government.

Mr Modi said the new law would save religious minorities such as Hindus and Christians from persecution in neighbouring Bangladesh, Pakistan and Afghanistan by offering them a path to Indian citizenship.

But the law does not apply to Muslims, which critics have said weakens India's secular foundations.

Mr Modi's ruling Hindu nationalist Bharatiya Janata Party denied any bias against the country's 180 million Muslims.

Hundreds of people supporting the new law clashed with those opposing it on Sunday, with the two groups pelting each other with stones in the Maujpur area in the north-eastern part of the city.

"There must be some miscreants who want to spoil the peace in the area. We will identify them and take action against them," senior Delhi Police official, Alok Kumar said.

"The situation is under control now," he said.

Mr Trump is expected to raise the issue of religious freedom with Mr Modi after a banquet dinner.

On Sunday, a separate protest also erupted in the northern Indian city of Aligarh, where protesters threw stones at the police, state administration official Chandra Bhushan Singh said.

The internet in the area was suspended until midnight.

Hundreds of thousands of people are expected to gather to greet Mr Trump in the city of Ahmedabad in Gujarat, in India's west, where he will address a rally of more than 100,000 in a newly-built cricket stadium, before a visit to Agra's renowned Taj Mahal and a summit with Indian officials and business leaders in New Delhi.

Half a dozen people said they had been offered 200 Indian rupees ($4.21) each by Mr Modi's ruling Bharatiya Janata Party to attend Mr Trump's rally, according to local media.

Slums get makeover ahead of Trump visit

Mr Trump is expected to visit the Gandhi Ashram in Ahmedabad during his visit. ( Reuters: Alasdair Pal )

At the Sabarmati Ashram, the former home of India's independence hero Mahatma Gandhi, labourers watered lawns and painted walls.

The modest complex is a possible 15-minute stop on for Mr Trump.

At the Saraniya Vas slum, authorities built a wall at least 1.8 metres high in places, shielding the settlement from Mr Trump's view.

While some are enthusiastic for Mr Trump's visit, many residents expressed anger.

"Priority should be given to us — at least the basics should be provided," said Sanjay Saraniya, a 27-year-old father of three, yards from the glossy tarmac of a newly-paved road and at least a dozen large billboards featuring Mr Modi, Mr Trump and his wife Melania.

"I wake up every morning and think about how I am going to earn enough money to feed my children."

ABC/Wires