NEW DELHI -- Long lines have grown longer, scuffles have broken out and chaotic scenes are being seen across India as millions of people wait to change old currency notes that have become worthless after the government demonetized high-value bills.

Angry scuffles broke out Saturday in New Delhi after ATM machines ran out of bills. Minor stampedes occurred in two places when thousands of people waiting in line surged forward to enter the building.

Paramilitary troops posted at banks in some of the most congested areas of the city walked among the crowd urging people to stay calm.

Earlier in the week, India's government made a surprise announcement that all 500- and 1,000-rupee notes had no cash value in an effort to tackle corruption and tax evasion.