A group of nine British and American diplomats were detained at gunpoint for several hours in Zimbabwe today after being stopped at a roadblock and attacked by both police and Robert Mugabe's "war veterans".

The United States reacted with fury to the incident, in which one of its embassy drivers was beaten up by a mob of around 40 people.

A State Department spokesman, Sean McCormack, said that the Americans would raise it at the UN Security Council later today and with Mr Mugabe's delegation at the world food summit in Rome.

"It is outrageous, it is unacceptable, and while this immediately incident has been resolved it will not be forgotten," Mr McCormack added.

The UK response, by contrast, was much calmer, although the Foreign Office formally summoned the Zimbabwean ambassador to explain the incident. In a statement this evening, David Miliband, the Foreign Secretary, said that it was "obviously a serious incident" but said that "there was no violence involved".

The group of five American and four British diplomats left Harare this morning in a three-vehicle convoy to meet activists from the opposition Movement for Democratic Change (MDC) in the town of Bindura, about 30 miles north of the capital.

But the house in which they were meeting was surrounded by police, who told the diplomats that they had to report to a local police station. Zimbabwean officials later said that the diplomats had been addressing an opposition rally.

Details remain unclear, but it appears that the diplomats refused and drove away. Shortly afterwards the convoy was blocked by an unmarked truck containing war veterans loyal to Mr Mugabe's Zanu (PF).

The US Ambassador to Zimbabwe, James McGee – who was himself briefly detained with other diplomats last month – told CNN from Harare that the confrontation turned violent.

"My people were stopped, detained," he said. "The police put up a roadblock, stopped the vehicles, slashed the tires, reached in and grabbed the telephones from my personnel. And the war veterans threatened to burn the vehicles with my people inside unless they got out of the vehicles and accompanied the police to a station nearby."

Sky News reported that two of the vehicles, including the British one, managed to escape by gunning their engines but the third could not get away.

Shortly before 4pm UK time, Downing Street said that the four British diplomats involved had all been released. The State Department later confirmed that the Americans had been released as weel.

Mr McGee, who was briefly detained himself last month with a group of fellow ambassadors including the British High Commissioner Andrew Pocock, said that the police should have contacted the Ministry of Foreign Affairs to deal with the diplomats.

"Instead in this lawless society that we call Zimbabwe the police decided to take action into their own hands and detaining my people for almost five hours now," he said.

“This country, this government, is not following their own laws and definitely not following any international laws," he said, adding there was a campaign of intimidation which was coming "directly from the top."

He added: "This is the co-ordinated campaign to try to intimidate us and people into not witnessing what’s happening in Zimbabwe.

"We will continue to do our job and we are not going to be intimidated into sitting inside of the embassies and not going out and seeing what’s happening in the country."

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