A fire has damaged the front doors and exterior of Australia’s Old Parliament House in Canberra.

The cause of the fire was not immediately clear, although a group of protesters championing indigenous rights had been gathering outside the building.

Some protesters told the media that the fire began as a traditional smoking ceremony got out of control. But one witness told Melbourne radio station 3AW that he heard protesters chanting “let it burn”.

Social media footage showed flames leaping up the doors, a thick plume of smoke rising above the building, and police dragging protesters away from the front steps.

The Australian Capital Territory emergency services said they were called to the scene just before noon and found the front doors on fire. The building was evacuated as a precaution and crews extinguished the blaze.

Protesters had earlier lit a fire at the building on December 21 and there had been daily protests outside the building for the past five days.

Deputy prime minister Barnaby Joyce said it was an “absolute disgrace” if the fire had been deliberately started.

“This is the parliament that for so long underpinned the freedoms we have as a democracy, and made the decisions that formed us as a nation, fighting for the increase of rights and corrections to our colonial past,” he said.

“If someone is trying to make a statement then it is a very bad one that will be received with overwhelming disgust,” he added.

The building was home to the federal parliament from 1927 until 1988, when a new building was opened.

The building is now listed on the National Heritage Register and is home to the Museum of Australian Democracy. The museum’s website said it was closed until further notice.