The police has arrested 18 members of the Construction and Development Party, the political arm of Jama'a al-Islamiya, while they were riding in a taxi on the Cairo-Alexandria desert road with weapons in the car.
The members of the party had five shotguns and two bulletproof vests, and were on their way to Rabea al-Adaweya square where supporters of President Mohamed Morsy are staging a sit-in.
Major General Amin Ezz Eddin, Alexandria's security chief, had received notification that a group of armed people were on their way to Rebea al-Adaweya to join protests to be staged on 30 June.
A police ambush was set up on the desert road and the vehicle was stopped. There were 18 passengers in the car.
Police seized the weapons in the car.
Besides the weapons seized, police also found batons and some Tagarod petitions. The passengers admitted they were headed to Rabea al-Adwayeya to join the protests.
A report of the incident was filed and the prosecution will open an investigation.