NAYPYITAW, Myanmar — Myanmar’s powerful army chief on Tuesday urged the country’s ethnic rebel groups to agree to a comprehensive cease-fire agreement now and stop wasting time on demands he described as impossible.

Speaking at the annual Armed Forces Day parade, Senior Gen. Min Aung Hlaing said decades of armed conflict with rebel groups had caused Myanmar’s development to lag behind its neighbors.

Myanmar’s military ruled the country for a half-century during which it was accused of widespread abuses before partially handing power to a civilian government in 2016. It is still in charge of security matters and still faces accusations of rights abuses.

The military has been firmly behind a formal National Ceasefire Agreement but only a few of the ethnic armies have signed up to it. Several of the most powerful have refused and want a re-negotiation as the continue to seek greater political and economic autonomy.

Heavy combat continues intermittently in areas settled by the Kachin and the Shan, who insist they want a comprehensive political solution before laying down their arms.

In his speech, Min Aung Hlaing said ethnic armed groups should stop delaying.

“Instead of pointing to the past and finding faults, it is now high time to learn the lessons of the past and conduct for the country’s development,” he said, according to a translation provided by the military.

The military chief blamed differences among various ethnic and religious groups on a divide-and-rule policy of Britain, Myanmar’s former colonizer, and suggested that all parties put aside their grudges from the past.

Myanmar’s civilian government led by Aung San Suu Kyi has pledged that her government’s priority is to implement peace and national reconciliation, though the military is still embroiled in combat with the Kachin and the Shan and has been conducting a brutal counter-insurgency campaign against the Muslim Rohingya minority.

During the previous military-backed civilian government, eight ethnic armed groups had signed the cease-fire agreement; two smaller ethnic groups signed the agreement with Suu Kyi’s administration last month.

Tuesday’s parade, at a huge ground outside the capital Naypyitaw, featured more than 11,000 soldiers, and fly-pasts by fighter jets and helicopters.