COLOMBO, MAY 11 (AP/UNB) - Doctors in Sri Lanka have gone on strike to demand an increase in their monthly allowance, crippling services at the country's state-run hospitals.

The Government Medical Officers Association says the doctors decided to take action Friday because the authorities had failed to fulfill their promise to increase their disturbance, availability and transport allowance.

The GMOA says the government promised in 2008 to increase the monthly allowance from 15,000 rupees ($115) to 29,000 rupees ($223).

As a result of the strike, patients arriving for treatment at state-run hospitals across the South Asian island nation faced severe difficulties. Sri Lanka's private hospitals are functioning as usual.

Such strikes are common in Sri Lanka's state-owned institutions.