Two leaders of the Islamist Wasat party that support ousted president Mohammed Morsi were arrested on Monday, dpa reported.
Wasat Party leader Abul-Ela Madi and his deputy Essam Sultan were arrested in an apartment in Cairo. Police seized large amounts of money in US dollars, euros and Egyptian pounds, local media reported.
Both politicians were transferred to Tora Prison, southern Cairo, where ousted president Hosny Mubarak is detained.
Madi and Sultan were staunch supporters of Morsi. Prosecutors issued arrest warrants for them along with leaders of Morsi's Muslim Brotherhood, for inciting violence.
The arrests come after dozens were killed in Egypt at the weekend in clashes that have continued unabated since the army ousted Morsi on July 3.
A security official said one policeman died on Monday of wounds sustained during the clashes between Morsi supporters and security forces on Saturday.
The Muslim Brotherhood group and allied Islamists say Morsi was ousted in a military coup.
The army and its supporters accuse the Brotherhood and Morsi of inciting violence in Egypt. The Brotherhood has vowed to continue protesting until Morsi is restored to power.
EU foreign policy chief Catherine Ashton was scheduled to meet with government officials on Monday in Cairo as well as representatives of the Brotherhood's Freedom and Justice Party.