Iranian authorities have detained executives of a major petrochemical firm for endorsing a strike by laborers over inadequate compensation and benefits in the southern energy-rich area, local media reported on Wednesday.

The private news agency disclosed that “a few executives” were apprehended for “aiding the actions of counter-revolutionary elements” and “coordinating strikes” at South Pars ventures. It added that more company officials would be arrested “in the coming days.”

The South Pars deposit in the Gulf, which Iran shares with Qatar, is the biggest known gas reserve globally and employs around 40,000 workers. According to Iran Labor News Agency (ILNA), South Pars workers “have continued to voice their collective demands,” calling for a “79% increase in wages” as well as an “end to discrimination” and the right to “freedom of association.”