Yilkal Getnet, who heads the opposition Blue party, said on Sunday that police raided their headquarters in the capital, Addis Ababa, on Saturday night and beat up some party members. He said police also seized banners and equipment that would have been used during a street protest on Sunday.
He said the rally was meant to highlight the continued detention of some journalists and Muslim activists.
Ethiopia has charged at least 28 Muslims activists with terrorism. But those activists say they have been unfairly targeted by the government, which they accuse of harassment.
A spokesperson for Ethiopian police was not immediately available for comment.
– AP