Egyptian police have arrested at least nine members of the opposition Muslim Brotherhood - in the latest round of detentions targeting the group.

The arrests are part of an ongoing crackdown on the Muslim Brotherhood, and they follow last month's passage of constitutional amendments giving the government sweeping security powers. The Brotherhood and other groups boycotted the referendum.

On Wednesday, human rights group Amnesty International sharply criticized Egypt for what it said was a systematic pattern of abuse, torture and arbitrary arrests. Egypt called the report's findings "offensive" and "unfair."

The Muslim Brotherhood is the largest Egyptian opposition group, holding one-fifth of the seats in parliament. Members run as independents because the group has been outlawed since 1954.

Some 40 Muslim Brotherhood members face a military tribunal on charges of money laundering and terrorism.

Some information for this report was provided by AP and Reuters.