Goa, Aug. 31 -- Thousands of Australians took to the streets on Sunday in anti-immigration rallies, with organisers controversially singling out Indian migrants. Promotional material for the "March for Australia" rallies claimed the rise in Indian migration was leading to cultural "replacement," sparking widespread criticism.

Large demonstrations were seen in Sydney, Melbourne, Canberra and Townsville, where protestors carried national flags and anti-immigration placards. In Sydney, 5,000-8,000 people gathered, while Melbourne saw tense clashes between marchers and counter-protesters, resulting in six arrests and two injured police officers.

Organisers described their movement as grassroots and denied extremist ties, but the presence of...