At least 129 people died at a soccer stadium in Indonesia when fans invaded the pitch and police responded with tear gas, triggering a stampede, authorities said Sunday, according to the AFP news agency.

The incident took place as Arema FC supporters at the Kanjuruhan stadium in the eastern city of Malang stormed the pitch late on Saturday after their team lost 3-2 to Persebaya Surabaya.

Police, who characterized the unrest as "riots", tried to persuade fans to return to the stands and fired tear gas after two officers were killed.

Many of the victims were trampled to death, according to police.

"34 people died inside the stadium and the rest died in hospital," East Java police chief Nico Afinta said in a statement on Sunday.

Afinta said many people were crushed and suffocated when they ran to one exit.

Photos from inside the stadium during the stampede showed huge amounts of tear gas and people clambering over fences, according to AFP.

The Indonesian government apologized for the incident and promised to investigate the circumstances surrounding the stampede.

The local soccer association has suspended matches for one week, banned Arema FC from hosting home games for the rest of the season and said it would send an investigation team to Malang to establish the cause of the crush.