In a further clampdown by the Ethiopian government following last month's controversial parliamentary elections, opposition officials say security forces have begun arresting opposition supporters and closely monitoring opposition party leaders.
The campaign manager of the main opposition Coalition for Unity and Democracy party, Berhanu Nega, tells VOA at least 10 of his staff members were arrested and taken away by security forces Wednesday.
He says the leadership of his party is also under constant surveillance.
"They have put one of our executive committee members in an office arrest, it's not even a house arrest," he noted. "They told him not to leave his office. He stayed the night in the office, and he's still there. They have arrested numerous of our members, including most of our office employees. I think the idea is to simply paralyze the organization from functioning. As for all the other leaders, they [security] are just simply escorting us wherever we go."
Mr. Berhanu says another coalition official was detained overnight in a restaurant.
It is not known how many opposition supporters and members have been arrested. But European Union election observers late Wednesday condemned the detentions and other harassment against the opposition.
The surveillance and arrests are part of a week-long crackdown on opposition members and demonstrators protesting provisional results of the country's May 15 elections.
Preliminary results indicate a victory for the ruling Ethiopian People's Revolutionary Democratic Front. But opposition parties and others, including the chairman of Ethiopia's rebel Oromo Liberation Front, have accused the ruling coalition of massive vote rigging and fraud.
At least 22 people were killed and scores injured during the week's violence.
The press credentials of Ethiopian journalists working for Voice of America and the German broadcaster, Deutsche Welle, were also revoked during the week.
Most shops in the capital, Addis Ababa, were closed Thursday, and taxis were not operating.
Ethiopian Information Minister Bereket Simon denies that any opposition leaders have been detained. But he says some supporters and members were arrested because they were, in his words, "bent on inciting violence."
Mr. Bereket says those who have been charged with inciting violence will be treated fairly, and will have their constitutional rights respected.
"Any person who has been instigating violence and pushing people to take unlawful action must be accountable for what he did," said Mr. Bereket. "In areas where we have objective evidence to support our charges, we have taken these people to the court. Definitely, we are going to investigate the cases, and that will follow all the legal procedures this country has."
Mr. Bereket calls the surveillance of opposition leaders a precautionary measure to prevent more unrest.
The Coalition for Unity and Democracy's Mr. Berhanu says he doubts that a peaceful solution can be reached at this time.
"I just cannot imagine how a negotiation for peaceful resolution of these election-related problems could be made, when you arrest the leadership, or you restrict their movement and deliberately try to destroy the legitimate legal organization," Mr. Berhanu added.
The May 15 election was the third since the ruling coalition took power in 1991. On the day of the election, Prime Minister Meles Zenawi imposed a month-long ban on all demonstrations.
International observers monitoring polling stations have reported incidents of irregularities and allegations of intimidation.