British diplomats detained at gunpoint by Mugabe thugs after they visit Zimbabwe opposition

British diplomats in Zimbabwe were held by armed thugs loyal to President Robert Mugabe yesterday in a tense stand-off.

The envoys, who were investigating political violence, were released unharmed after more than an hour.

But American diplomats held with them had earlier been forced to smash through a roadblock after a mob broke their windscreens, slashed their tyres and threatened to burn them in their vehicles.

Foreign Secretary David Miliband condemned the 'serious' incident while the White House described it as 'outrageous.'

The Zimbabwean High Commissioner in London was summoned to the Foreign Office to explain what happened and the U.S. State Department demanded an explanation from the Zimbabwean ambassador in Washington.

James McGee, the U.S. ambassador to Zimbabwe, said he believed the order to detain the diplomats had come 'directly from the top'.

He added: 'What they are trying to do is intimidate diplomats from travelling to the countryside to witness the violence being perpetrated against the population.'

Mr McGee, who was not with the convoy, said his staff were threatened by Mugabe's unofficial 'war veterans' armed militia.

Precise details of what took place were unclear last night but police are said to have surrounded the American diplomats after they met activists from Morgan Tsvangirai's opposition Movement for Democratic Change.

Poll violence: A poster with a portrait of Zimbabwean President Robert Mugabe during a protest in neighbouring Namibia

The mood is said to have turned 'ugly' when the police were joined by war veterans loyal to Mugabe's Zanu PF party.

Mr McGee said: 'Police put up a roadblock, stopped the vehicles, slashed the tyres, reached in and grabbed telephones from my personnel, and the war veterans threatened to burn the vehicles with my people inside unless they got out and accompanied police to a station nearby.'

A Zimbabwean driver working for the U.S. embassy is said to have been beaten in front of the diplomats before the war veterans, supported by the police, ran amok and tried to take the keys from the vehicles. A U.S. vehicle reportedly managed to break out but had all four tyres punctured by metal spikes across the road so that it was forced to travel for up to 20 miles on the metal wheel rims.

The U.S. diplomats were then held at a second roadblock near the capital Harare by heavily-armed police where they were later joined by the British envoys.

The Britons and Americans were prevented from leaving until government officials were sent from Harare to escort them back to the city.

High risk: Zimbabwe opposition Movement for Democratic Change leader Morgan Tsvangirai (C) visits a party member who was a victim of post election political violence in May

Opposition and human rights groups have accused Mugabe of orchestrating violence and intimidation in the run-up to a June 27 presidential run-off.

Police spokesman Wayne Bvudzijena denied the diplomats had been threatened, saying police had been trying to rescue them from a threatening mob.

'It's unfortunate when diplomats behave like criminals and distort information,' he added. 'It is a very sad situation.' Zimbabwe's deputy information minister Bright Matonga said the diplomats were attending a rally of the opposition shortly before trouble flared.

Mr Matonga said: 'There was a fight there. Police were called in. The diplomats fled. On their way back to Harare, they were stopped at a police roadblock.

'They were asked to disembark from the vehicle. They refused, and the police told them they were not going anywhere unless they got out of the car and they should respect the laws of the country, unless they have something to hide.'

Mr Miliband said of the incident: 'I think it gives us a window into the lives of ordinary Zimbabweans, because this sort of intimidation is something that is suffered daily, especially by those who are working with opposition groups.

'It's a window into lives that are marked by brutal intimidation, by torture and, in 53 cases that have been documented over the last few weeks, by death.

'It's very important that the international community plays its role by ensuring that for the election on June 27 there are international monitors, properly accredited, who are able to ensure that despite the ravages in Zimbabwe at the moment there is an election that allows the democratic will of the Zimbabwean people to be heard loud and clear.'

Shadow foreign secretary William Hague said: 'This is a flagrant breach of Zimbabwe's obligations, under international convention, to protect diplomatic staff on their territory.

'It is an outrage that the Mugabe regime continues to inflict violence on the Zimbabwean people and now on those who would help them.'

Outrage: Mugabe in Italy

Mugabe caused international outrage when he appeared earlier this week at a Rome summit to condemn Britain and its allies for trying to wreck the Zimbabwean economy through 'illegal' sanctions.

He was condemned for attending the UN food crisis conference while his countrymen starve as a result of his disastrous land reform policies. He finally emerged yesterday from his luxury Rome hotel after not having been seen for 36 hours.

• Zimbabwe's social welfare minister Nicholas Goche said last night that all foreign aid groups must stop field work in the country.