Crowds of demonstrators were seen running away from the scene outside parliament in the capital Jakarta, according to a Reuters witness, while Kompas TV said rocks had been thrown into the complex.
The rally was one of several across Indonesia on Monday, including in South Sulawesi, West Java and Jakarta, where hundreds of students wearing neon jackets had marched towards parliament to complain about rising goods costs and the prospect of the president outstaying his two-term limit.
Jakarta police chief Fadil Imran told a news conference that a university lecturer who was participating in the demonstration sustained “grave” injuries after a “non-student” group battered and stomped on him. Six police officers who tried to help the lecturer were also injured, he added.
He did not say why the group had targeted the lecturer.
Jokowi, as the president is known, on Sunday sought to dampen speculation of a plan being hatched by his allies to keep him in power longer.
The idea of extending his tenure either by changing the constitution or delaying the 2024 election, has gained momentum lately in the world’s third-largest democracy after some influential political figures publicly backed it.
“What’s clear is how the elites are forcing themselves to delay the election, and that’s what hurts the constitution,” said Muhammad Lutfi, a student attending the protest.
The idea of allowing more than the maximum two, five-year terms as president has fueled concern about a threat to hard-won democratic reforms.
On Sunday, for a second time in under a week, Jokowi, 60, urged ministers and security chiefs to cease discussion of the issue to prevent public speculation and said it was clear that an election would be held in February 2024, as planned.
He has been criticised for his ambiguous stance on the issue, calling it a slap in the face and just “an idea”, but without explicitly rejecting it or ruling out staying in power longer.