Australian PM Julia Gillard and leader of the opposition Tony Abbott had to be rescued by riot police after angry protesters surrounded them.
About 50 police escorted the pair from Canberra's Lobby restaurant after it was surrounded by some 200 supporters of the city's Aboriginal Tent Embassy.
Mr Abbott had reportedly angered them by suggesting it was time for the camp - marking its 40th year - to come down.
The pair had been at a ceremony for the inaugural National Emergency Medals.
The honours - presented as the country marked Australia Day - were introduced to recognise those who served their communities during events such as the 2009 bushfires in Victoria and the floods in Queensland in 2010 and 2011.
But riot police were called to the restaurant at about 14:30 local time as protesters gathered outside, with people banging on the glass yelling "shame" and "racist".
Ms Gillard and Mr Abbott were reportedly forced to wait 20 minutes before police escorted them through a side door.
According to the BBC's Duncan Kennedy, chaos ensued as a bodyguard grabbed Ms Gillard by the shoulders and shoved her into a waiting car.
The prime minister appeared to have stumbled in the process and was missing a shoe. Protesters continued to bang on the car's roof and the bonnet as it sped off.
Supporters had gathered for a three-day Corroborree for Sovereignty to mark the 40th anniversary of the tent embassy.
Local media reports suggested some had been angered by Mr Abbott's suggestion in a TV interview that it was "time to move on" from the camp in light of current plans to recognise indigenous people in the country's constitution.
The Australian newspaper reported that one of the embassy's founders, Michael Anderson, had accused the opposition leader of inciting a riot. "He said the Aboriginal embassy had to go; we heard it on a radio broadcast," it quoted Mr Anderson as saying. "We thought no way, so we circled around the building."
The tent embassy was established in 1972 by four men as a protest against the prime minister of the time's refusal to acknowledge indigenous land rights.
Speaking at an Australia Day function at her official residence after the incident, Ms Gillard said she was fine.
"I mean the only thing that really kind of angers me about it is that it disrupted such a wonderful event for great people," she said.
"I am made of pretty tough stuff and the police did a great job."