The swearing-in of Zimbabwe's new power-sharing cabinet has been marred by the arrest of a minister.
Roy Bennett, the opposition MDC's choice to become deputy agriculture minister, was seized near a Harare airport before the ceremony.
The MDC said police later fired shots in the air to disperse supporters from a police station where he was held.
The new cabinet was sworn into office by President Robert Mugabe two-and-a half hours behind schedule.
The delay was also caused by a dispute over several extra Zanu-PF ministers of state who had turned up to be sworn in.
The issue was only resolved after intense closed-door negotiations. The swearing-in came nearly a year after disputed polls.
On Friday, the MDC said that "police have started firing live ammunition in the air and have brought dogs in an attempt to disperse hundreds of MDC supporters that had surrounded Mutare police station" in eastern Zimbabwe.
KEY CABINET APPOINTMENTS
Emmerson Mnangagwa, seen as a possible successor to Robert Mugabe, defence
Sydney Sekeramayi, ex-defence minister, state security
Joseph Made, ex-agricultural minister, agriculture
Patrick Chinamasa, chief negotiator of power-sharing deal, justice
Kembo Mohadi, former home affairs minister, home affairs
Tendai Biti, lawyer and ex-student leader, finance
Giles Mutsekwa, lawyer with a military background, home affairs
Henry Madzorera, trained doctor, health
Eric Matinenga, lawyer who defended Mr Tsvangirai on treason charges, constitutional affairs
Roy Bennett, former farmer, arrested, deputy agriculture minister
MDC spokesman Ian Makone said earlier that Mr Bennett was arrested at the small Charles Prince airport, north-west of the capital, Harare.
In a separate dispute over the swearing-in ceremony, one MDC official was quoted as saying that the additional Zanu-PF officials were junior ministers, who are due to be sworn in next week.
Under the power-sharing agreement, Mr Mugabe's Zanu-PF is to have 15 posts and the two factions of the Movement for Democratic Change (MDC) 16, under Prime Minister Morgan Tsvangirai.
On Thursday, Mr Bennett told the BBC that he was in hiding as the security services had issued an arrest warrant for him.
The former MP has long been a controversial figure.
A white farmer who lost his property under Mr Mugabe's land reform programme, he was in prison from October 2004 to June 2005.
The sentence was imposed by other MPs after he pushed a government minister during an argument in parliament over land reform.
He has only recently returned to Zimbabwe after more than two years in South Africa, where he fled after police sought his arrest in connection with an alleged plot against Mr Mugabe.
A western diplomat described his arrest as a deliberate provocation by Mr Mugabe and a supreme act of bad faith and contempt, reports the BBC's Andrew Harding, who is in Zimbabwe despite a ban on the BBC reporting there.
Zimbabwe's messy experiment in power sharing is, as expected, getting off to a bumpy start, our correspondent says.
'Mugabe is solution'
Before the swearing-in ceremony, MDC leader Mr Tsvangirai told the BBC the country was "on its knees".
He said the humanitarian situation needed to be tackled, schools re-opened and the cholera epidemic which has killed some 3,400 people ended.
"We have to find a solution to the country's crisis," he said. "Mugabe may be part of the problem, but he's also part of the solution. I am sure the reverse will also apply to me from their side."
Morgan Tsvangirai: 'The country is on its knees, but we cannot solve everything'
The economy is in meltdown, with the local currency virtually worthless and unemployment of some 90%.
Correspondents say Friday's hitches show how difficult it will be for the coalition to work.
Many of the Zanu-PF ministers have served in cabinet since Mr Mugabe was first elected in 1980.
Several MDC ministers have been beaten or arrested for their opposition to Mr Mugabe.
Zanu-PF's Emmerson Mnangagwa, the new defence minister, has long been seen as a potential successor to Mr Mugabe and was accused of links to the 2008 election violence against the MDC.
Sydney Sekeramayi, a former defence minister, takes the state security ministry which controls the feared Central Intelligence Organisation.
MDC Secretary General Tendai Biti takes on the enormous challenge of finance, while as Health Minister Henry Madzorera is now in charge of tackling the cholera outbreak.
The formation of the government has also gone ahead despite MDC concern about the fate of imprisoned activists.
The MDC says more than 30 people, including 72-year-old man Fidelis Charamba, are still being held after being abducted and illegally detained.
They have been accused of subversion and recruiting fighters to overthrow Mr Mugabe - charges denied by the MDC.
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