CAIRO (AFP) - A policeman was killed on Sunday and an army officer was wounded in Egypt's city of Port Said, the army said, after the authorities decided to move prisoners awaiting a verdict over alleged involvement in a deadly football riot.

The military said the policeman died and the military officer was hit in the leg when they were struck by gunshots fired by unknown assailants outside the headquarters of the Port Said governorate in north-east Egypt.

A health ministry bulletin earlier said 253 people were injured in the clashes.

The court verdict, expected next Saturday, is for the remaining 39 defendants in a case which resulted in death sentences in January for 21 defendants, sparking clashes that killed at least 40 people.

A security official said earlier that protesters threw petrol bombs and stones at the police station in the restive Suez Canal city, where a general strike entered its third week. Police responded with tear gas.

The interior ministry said it decided to move prisoners from Port Said, starting with the 39 remaining defendants over the February 2012 football violence, because it wanted to avoid unrest.

Last year's football riot which killed 74 people, mostly supporters of a visiting Cairo team, exacerbated Port Said's isolation, residents of the city say.

Protesters on Saturday torched a police station in Port Said and prevented fire engines from reaching the blaze.

Residents of Port Said and other canal cities have long complained that Cairo marginalises them.