A spokesperson travelling alongside Morgan Tsvangirai speaks about the situation
Zimbabwe opposition leader Morgan Tsvangirai has been detained by police during campaigning for the country's presidential election, his party says.
A convoy carrying the Movement for Democratic Change leader was stopped at a police roadblock at 1000 GMT, party spokesman Nelson Chamisa said.
The MDC leader and his entourage were taken to a police station in the far west of the country, said Mr Chamisa.
"It appears they want to disrupt our campaign programme," he said.
It comes as Zimbabwe prepares for a run-off election between Mr Tsvangirai and President Robert Mugabe on 27 June.
The US said the Mr Tsvangirai's detention was "deeply disturbing", and the EU presidency, currently held by Slovenia, called for the opposition leader's immediate release.
Mr Chamisa said police stopped Mr Tsvangirai and his officials while they were driving to a rally as part of his presidential campaign.
The entire group - including the party's vice-president, national chairman and security personnel - are currently being "illegally detained" at the police charge office in Lupane, he said.
MDC supporters say they have been attacked by Zanu-PF supporters
Mr Chamisa called for Mr Tsvangirai's immediate release, adding that without the intervention of the United Nations and the international community it would be impossible to hold free and fair elections in Zimbabwe.
MDC campaigning efforts have been severely hampered, with four other party leaders being arrested in the run-up to this month's election.
The party says 58 of its supporters have been killed by pro-government henchmen since March's national elections.
In the latest political violence, two MDC supporters were burned to death by suspected Zanu-PF supporters.
There are fears for the lives of four other MDC supporters after Tuesday's attack in the southern town of Jerera.
MDC Masvingo provincial chairman Wilstaf Stemele told the BBC that Zanu-PF supporters had doused the blankets of the two men with petrol before setting them on fire.
He said the victims had not yet been identified as their bodies had been burnt "beyond recognition".
The government says the scale of the violence has been exaggerated and blamed the MDC for instigating attacks.
Speaking in Bulawayo on Tuesday, Mr Tsvangirai said: "Mugabe is determined to turn the whole country into a war-zone in order to subvert the will of the people and steal the June 27 election by any means possible.
"But we will not stop campaigning, the people will not stop supporting the MDC and together we will defeat this illegitimate and desperate regime."
Meanwhile, Human Rights Watch has criticised the Zimbabwean government for restricting the work of aid agencies operating in the country.
The operations of one of the largest groups - Care International - have been suspended amid allegations the group had been campaigning for the opposition.
Care denies that it "has encouraged or tolerated any political activity".
Mr Mugabe is currently attending a UN-sponsored summit on the global food crisis in Rome, where he blamed Western sanctions for Zimbabwe's economic woes.
Some four million Zimbabweans - a third of the population - are believed to need food aid this year.
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