The Ethiopian government is ramping up a campaign of intimidation against opposition politicians, journalists and rights activists ahead of national elections in May, a rights group said on Wednesday.

The Horn of Africa country's election will be the first since a government victory in 2005 was disputed by the opposition. About 200 street protesters were killed by security forces and the main opposition leaders imprisoned.

Prime Minister Meles Zenawi said they were trying to topple him.

New-York based Human Rights Watch said the government had arrested and imprisoned opposition politicians for varying terms since the 2005 poll.

"Expressing dissent is very dangerous in Ethiopia," Georgette Gagnon, Human Rights Watch (HRW) Africa director, said in a statement.

One of the country's most popular opposition leaders, Birtukan Mideksa, has been in prison for more than a year, accused of violating a pardon that released her and other opposition leaders jailed after the 2005 street violence.

The Ethiopian government dismissed the report.

source: Reuters