Indigenous protesters in Ecuador have paraded a group of captured police officers on stage in a brazen show of defiance to the government of Lenín Moreno, as protests against austerity-measures dragged into a second week.

Eight uniformed officers were brought onto a stage and forced to address a crowd of thousands of activists who have occupied the Casa de Cultura theatre in the capital Quito. A group of journalists, including the Guardian, were also temporarily prevented from leaving the theatre.

The officers looked scared but were not physically harmed as they were asked to remove their helmets, bulletproof vests and boots. The lone female officer in the group was seen wiping away tears.

Jaime Vargas, leader of the indigenous confederation Conaie called on the officers to join opposition protesters in their campaign against the removal of fuel subsidies which has triggered Ecuador’s worst unrest in a decade.

“We’re going to radicalise with more force, my friends,” said Vargas, before sending a direct message to the president: “Don’t play with indigenous people.”

Vargas, complained that media coverage of the protests had ignored police brutality, before calling local television crews on stage and ordering that they broadcast live.

At least three private broadcasters complied, as indigenous and trade union leaders took it in turn to address the crowd. But the mood turned violent as local TV reporter was attacked by a mob as he tried to leave the building. Other activists attempted to defend the journalist but he was left unconscious and bleeding from the head.

Thousands of protesters from across the country – many in traditional indigenous dress – have descended on the capital to protest Moreno’s austerity measures.

Violence has flared across the country as demonstrators clashed with police, looted shops and blocked highways.

Ecuador’s human rights ombudsman’s office said an indigenous leader and four other people have died. But a spokesman for the president’s office said on Thursday that only two people had died in the clashes.

José Valencia, Ecuador’s foreign minister, said the government wants dialogue but will not negotiate under the threat of violence and vandalism.

“This is an extremely critical situation which is not a decision of the indigenous leaders – we trust their word,” he told the Guardian.

“We have evidence that this is the result of calls by opposition leaders to use violence, to take control of public institutions and roads and attack the forces of order with violence,” he said.

He denied reports that police had used excessive force he said they had followed “strict protocols [which were] drawn up under international norms”.

Valencia said around two dozen foreigners, including Venezuelans, had been arrested.

Moreno, 66, has accused his predecessor and one-time mentor Rafael Correa of fomenting the unrest. He has also accused Venezuela of backing a plot to topple his government, without providing evidence.

The interior minister María Paula Romo tweeted that 17 Venezuelans had been detained leaving Quito’s international airport on Thursday.

The government says more than 750 people have been detained and some 80 police officers injured as a result of the clashes.

Fuel subsidy cuts were announced of part of a $4.2bn funding plan with the International Monetary Fund, as Moreno tacked further away from the leftwing policies of Correa.

“There’s a lot of uncertainty about what might happen” Michael Shifter, president of the Inter-American Dialogue, told the Associated Press. “The big lesson is that it’s very difficult to go from populism to a more orthodox economic policy.”