More than 100 protesters have gathered in Washington DC to express their fears about a huge oil pipeline which will cross four states in the US Midwest.

The $3.7bn (£2.8bn) Dakota Access pipeline has prompted legal challenges, notably in North Dakota where Native Americans have halted its construction.

It will run 1,168 miles through Iowa, Illinois, and North and South Dakotas.

Outside the US District Court in the US capital, environmental activists made their feelings clear.

They believe the transporting of up to 570,000 barrels of crude oil a day will imperil local waterways.

At the scene – Courtney Subramanian, BBC News, Washington

Dozens of protesters convened outside the US District Court, with environmental activists and members of the Standing Rock Sioux tribe uniting behind one message – water is life.

Generations of native Americans, both young and old, shared personal accounts of why halting the pipeline was important to them as crowd members cheered in support.

The crowd was studded with signs bearing the words “native lives matter”, “water is life” and “be on the right side of history, no DAPL.”