20091218

KHARTOUM (Reuters) - Election observers in Sudan said on Friday they were gravely concerned about government crackdowns on opposition rallies that undermined "political rights and fundamental freedoms" ahead of polls in April.

Riot police used tear gas to break up two demonstrations in Khartoum this month as tension mounted in the build-up to the first full multi-party election in the oil-producing nation in 24 years.

International observers from the Carter Centre called on the government to investigate reports of police brutality during the rallies, end arbitrary arrests and release "persons detained while conducting peaceful political activities".

The election is one of the centrepieces of a faltering 2005 peace deal that ended two decades of north-south civil war.

The main political force in south Sudan and opposition groups organised the rare demonstrations this month in streets around Sudan's parliament to call for a raft of democratic reforms ahead of the poll.

The interior ministry ruled both events were illegal, saying organisers had not asked for permission. Security services detained three leading members of the south's dominant Sudan People's Liberation Movement (SPLM) and scores of supporters.

"The Centre is gravely concerned by the recent action of the security forces in Khartoum to restrict legitimate activity related to the exercise of freedom of assembly, association and speech," a report by the observers said.

It also condemned attacks on the offices of north Sudan's dominant National Congress Party in two towns in south Sudan, and reports of harassment of minority parties in the south.

The report congratulated Sudan on holding a broadly peaceful voter registration exercise which, authorities said, reached more than three quarters of eligible voters in Africa's largest state.