Actor Mark Ruffalo is among those calling for a stop to water service shutoffs in Detroit, where he joined a massive protest march outside Cobo Center Friday.

Ruffalo, who starred in the blockbuster film “The Avengers,” said people “need to know what’s going on” with the water issue in Detroit.

United Nations experts say water shutoffs due to overdue bills is a violation of international human rights.

The Detroit Department of Water and Sewerage stepped up the shutoffs in March to collect some of the nearly $90 million owed by residents, businesses and other customers with past-due accounts. Through June, more than $43 million was owed on over 80,000 city residential accounts.

Coming from California to protest, SEIU's Terrence Long asked, "Because the city has mismanaged its funds, why is that people should suffer?"

The water department estimates about 90,000 active customers are delinquent on their bills. Spokesman Bill Johnson says service has not been shut off to anyone who has come to them with a “legitimate problem” in paying their bill.

The demonstration was organized by the group National Nurses United, which claims the shutoffs pose a public health emergency. The group’s co-president, Jean Ross, called the shutoffs “inhumane.”

Meantime, a separate demonstration outside a business linked to performing the shut-offs prompted police to make nine arrests.