The clashes erupted after two people were sentenced to six months in prison by a military court.
Ahmed Fayek, a member of 6 April in Marsa Matruh said there were four people on military trial, two were sentenced to six months and two were acquitted.
Khaled Al-Senini the spokesperson of the United Revolutionary Movement in Marsa Matruh, said the convicted were caught smuggling cigarettes along the Libya border and were arrested a long time ago but the verdict came out on Tuesday.
He added that after the military trial, it is routine that the convicted are taken to the police station before being taken to prison.
Police fired teargas canisters and fired warning shots in the air.
Fayek said the clashes have left two injured with gunshot wounds in the leg. They have been taken to a hospital. It is not yet known whether they were on the side of the police or the families.
Marsa Matruh’s governor is a military man, General Ahmed Helmy Fathi Al-Hatimi. He was appointed by President Mohamed Morsy, replacing another military man, after residents demanded an end to military dominance over Marsa Matruh.