Media playback is unsupported on your device Media caption Native American tribes come together to protest planned pipeline

The Green Party candidate for president has been charged with criminal trespass after being accused of vandalism at an oil pipeline protest in North Dakota.

A video appeared to show Jill Stein preparing to spray-paint a bulldozer.

She was protesting over the Dakota Access Pipeline, which is opposed by environmental and Native American groups who fear its impact.

"I approve this message," she is accused of writing on the blade of an earth-moving machine.

In a statement following the news of criminal charges, Mrs Stein said she hopes "the North Dakota authorities press charges against the real vandalism taking place at the Standing Rock Sioux reservation: the bulldozing of sacred burial sites and the unleashing of vicious attack dogs".

A judge has issued a warrant for her arrest but it is not known whether she intends to turn herself in.

She and her Green Party running mate Ajamu Baraka are charged with misdemeanour counts of criminal trespass and criminal mischief.

Image copyright Twitter Image caption Mrs Stein tweeted this image of her spray-painting the bulldozer

Since April over 3,000 people have been protesting about the pipeline. In recent days, private security forces have been using attack dogs to clear protesters.

Mrs Stein was also arrested during her 2012 campaign. She was protesting outside a debate to which she was not invited.

The 1,100 mile (1,770 km) crude oil pipeline passes close to Native American burial groups and is opposed by over 200 tribes.

A judge has temporarily forced the Texas-based Energy Transfer Partners to halt construction, and is due to decide on Friday whether to withdraw the company's building permits.