Riot police were deployed in force when a convoy to Gaza was proposed
Egypt's outlawed Muslim Brotherhood movement says 32 members have been detained for joining protests aimed at breaking the Gaza Strip blockade.
The group said 14 people were held in Port Said, 12 in Fayyoum and a number of others in Cairo and Beni Sueif.
The Egyptian government co-operates with Israeli-led sanctions against the Gaza Strip, which is controlled by the Palestinian Islamist movement, Hamas.
Many Egyptians, including the Muslim Brotherhood, disagree with the policy.
The Brotherhood is Egypt's largest opposition group but is officially banned by the authorities.
Earlier in October, Egyptian police blocked a convoy organised by opposition groups to carry medical supplies to the Gaza Strip.
Reports said at least 15 people were detained in Cairo - some of them linked to the Muslim Brotherhood.
Under an agreement brokered by the US in 2005, the Palestinian Authority, Israel and European Union monitors supervise the Rafah crossing between Gaza and Egypt. Egypt has co-operated with this.
Hamas, which has governed Gaza since June 2007, has been kept out of this arrangement.
The Egyptian government has also co-operated in the Israeli blockade of Gaza, which Israel says aims to undermine support among Gaza Palestinians for the Islamist movement Hamas.
The crossing at Rafah is closed almost all of the time.