Zimbabwe's High Court on Monday ordered police to allow lawyers access to opposition leader Morgan Tsvangirai, who was said to be "battling for his life" after suffering head injuries while in police custody.
Police detained Mr Tsvangirai and dozens of other opposition figures yesterday and killed a man while breaking up a prayer meeting organised in defiance of a ban on political rallies. Rights groups have alleged the opposition leader and other politicians were tortured.
United Nations Secretary-General Ban Ki-moon expressed concern about the detention, echoing international condemnation against the Zimbabwean government over rights abuses.
A lawyer for Mr Tsvangirai said the High Court ordered police to grant access to the head of the opposition Movement for Democratic Change (MDC) and the other detainees.
"A provisional order was issued that we have access to our clients, that they should be taken to hospital where necessary and that they should be taken to court by 12 [pm local time] tomorrow [Tuesday] failure of which they should be released," Alec Muchadehama said.
Under Zimbabwe's laws, police can detain suspects for up to 48 hours before bringing them to court.
Earlier, lawyer, Innocent Chagonda, visited the MDC leader and said he was in bad shape. "He was swollen very badly. He was bandaged on the head. You couldn't distinguish between the head and the face and he could not see properly."
MDC vice president Thokozani Khupe said the party wanted all detainees freed immediately and pledged that the struggle against President Robert Mugabe would continue.
"President Tsvangirai is battling for his life at Borrowdale police station after he was brutally assaulted. He lost consciousness three times following the ... attack," she said.
Political tensions, which have been brewing over the soaring cost of living and Mr Mugabe's controversial rule, erupted when riot squads fought opposition youths in the capital for the second time in a month yesterday, where one person was killed.
A coalition of opposition, church and civic groups called Sunday's meeting to address Zimbabwe's political and economic crisis. Police ordered organisers to scrap it due to fears the opposition was launching a street campaign to oust Mr Mugabe.
UN chief Ban said the crackdown violated citizens rights to peaceful assembly, his spokeswoman Michele Montas said.