Egyptian police on Friday arrested nearly 50 members of the opposition Muslim Brotherhood who were staging anti-Israel demonstrations, a security official said.
They were rounded up after weekly prayers as they demonstrated against Israeli plans to build Jewish settlements in Arab east Jerusalem and place two West Bank shrines on a list of Israeli heritage sites.
The Brotherhood had urged Egyptians to take part in the protests across the country and the arrests took place in several provinces, the source said.
He said protesters chanted slogans denouncing Israel's plans as well as "the silence of Arab governments."
Friday's arrests were the latest targeting the Brotherhood ahead of upper house elections in April and lower house elections in October. The Islamists have accused the authorities of cracking down on them ahead of the polls.
Brotherhood lawyer Salah Abdul Maqsud said that among those detained were "prominent figures who could run in the elections."
In February deputy leader Mahmoud Ezzat was among 16 Brotherhood members arrested in a move denounced by the group as well as by international human rights watchdogs.
The New York-based Human Rights Watch said February's arrests dealt "a blow at hopes for genuinely free elections."
The Muslim Brotherhood is banned in Egypt but is tolerated, and police regularly arrest its activists.
Despite the ban, the Brotherhood controls a fifth of seats in parliament after it fielded candidates as independents in a 2005 election.
Police rounded up hundreds of Brotherhood activists last year. The group, founded in 1928, has renounced violence and says it wants to establish an Islamic state through peaceful means.