ABUJA, Nigeria (AP) — Doctors in Nigerian public hospitals on Wednesday kicked off a five-day strike to demand better conditions, leading to health care being shut for many patients.

The strike by the resident doctors became necessary after the government’s refusal to increase their salaries and pay arrears owed some of their members as well as to invest more in hospitals, according to Dr. Innocent Orji, president of the Nigerian Association of Resident Doctors, or NARD.

Although the current work stoppage doesn't affect specialist doctors or nurses, medical residents make up the bulk of health care workers in Nigerian government hospitals. Such strikes are also common with the public health sector lacking sufficient funding for many years despite the country’s huge earnings as Africa’s biggest economy and top oil producer.

Critics, meanwhile, point to the vast disparity between the government hospitals treating most Nigerians and the medical care abroad that is available to the country’s elite, including Nigerian President Muhammadu Buhari, who often travels to the U.K. for medical care.

Amid Nigeria's current economic crisis, the doctors in April threatened to go on strike but “we have not seen any positive sign from the government,” Orji told The Associated Press.

“The government has not called us to the negotiation table. Instead, what we have been getting is threats upon threats,” he said, adding that the warning strike could be extended if talks with the government fail to improve.