One of Nigeria’s main oil and gas trade unions on Thursday threatened to take industrial action over a staffing dispute with Chevron.

In a statement, the Nigeria Union of Petroleum and Natural Gas Workers (NUPENG) said it was prepared to take industrial action if the U.S. oil major did not comply with its wishes within seven days over a reduction of the company’s workforce.

Trimming its staff strength has always caused a rift between Chevron and the workers’ union.

Last year, the Nigeria Union of Petroleum and Natural Gas Workers and the Petroleum and Natural Gas Senior Association accused Chevron Nigeria Limited of planning to circumvent labour contract guidelines and sack some contract workers.

In a joint statement, the unions expressed worry over “the way and manner the Chevron management is executing the end of M15 and H15 contracts, which is ostensibly laced with hidden plans and intentions to unilaterally and heinously sack thousands of contract workers.”

They said this was despite ongoing intervention of the Federal Ministry of Labour and Employment as well as the established Labour Contract Staffing Guidelines in the oil and gas industry.

The statement was signed by PENGASSAN’s General Secretary, Mr Lumumba Okugbawa, and his counterpart in NUPENG, Mr Adamu Song.

It read in part, “While Chevron has decided to close M-15 and H-15 contracts by 31st of October, 2018, it is really disturbing to see the new contractors being engaged by Chevron management and whose labour contract will take effect on November 1, 2018, to start advertising all jobs, in spite of clear provision for ‘roll over’ of the existing workers on the jobs.”

A Chevron spokesman said he was unable to provide immediate comment.