A bomb has exploded in a car in Birmingham city centre.
The blast happened at 2230 GMT on Saturday close to New Street railway station, police said.
Police suspect an Irish dissident group is responsible - a warning was given but it was received too late to deactivate the device, officers said.
Officers attending the scene received minor injuries but no-one else was hurt.
Bomb disposal experts and Metropolitan Police officers are at the site, on Smallbrook Queensway.
Decontamination experts were also called to the scene after initial fears that anthrax was involved, although this was later ruled out.
Chief Inspector Ellie Bird, of West Midlands Police, said: "Early indications are that this is the work of an Irish dissident group.
"We did receive a warning, however that was far too late. We are concerned this could have had serious consequences."
She added: "It cannot and should not be connected with the incidents in America on 11 September."
Birmingham was the target of one of the Provisional IRA's worst atrocities when two pubs were blown up in 1974, leaving 21 people dead and scores injured.
No group has admitted responsibility for Saturday night's blast although suspicions are likely to fall on republican dissident group the Real IRA.
Chief Inspector Bird said initial eyewitnesses described seeing a white powder coming from rear of the vehicle and the emergency services feared an anthrax attack.
Two or three police officers were decontaminated as a precaution before it became apparent that the blast was the work of an Irish dissident group, she said.
Police were now conducting a thorough investigation into the explosion and a 1,000-metre cordon had been placed around the blast site.
"Until we are satisfied that it's safe, it will remain sealed off," she said.
Chief Inspector Bird said the explosion had taken place on a busy street in the heart of Birmingham city centre at a time when many people were heading for nearby nightspots.
Hotels and other premises in the area have been evacuated by police as a precaution in the event of another explosion, she told the BBC.
The blast appeared to have caused minimal damage and the car, which was not totally destroyed, was believed to have been an Audi.
"We are very relieved that there have been no serious injuries. It's very fortunate that there have been no casualties," said Ms Bird.
She said a coded warning had been received by an organisation - not the police nor the emergency services - that an explosive device had been placed in the area.
The blast came just hours after politicians in Northern Ireland found a way to rescue the peace process, which was thrown into disarray when David Trimble failed to be re-elected as the province's first minister.
Members of the cross-community Alliance Party - which represents both moderate Roman Catholics and Protestants - have decided to re-designate themselves as Unionists in a bid to save the Good Friday Agreement.
A new vote will be held on Monday.
Source: BBC News http://news.bbc.co.uk