Eighteen people have been injured in an explosion on one of the busiest streets in the Czech capital Prague.
Detectives inspect a car involved in the explosion
Witnesses say a hand grenade was thrown outside a casino near Wenceslas Square at about 1230 local time (1030GMT) on Sunday.
Most of those injured are not thought to be seriously hurt. Five were Britons and others were reported to be from the US, Ireland, Germany and Slovakia.
The blast is believed to be linked to feuds between criminal gangs.
The area where it happened has many shops and restaurants which are open on a Sunday and is
normally packed with tourists.
'Not a bomb'
Most of the injured were hit by shrapnel or glass from the explosion, emergency services spokesman Marek Uhlir told Czech state television.
Most were guests sitting close by in a garden terrace restaurant outside the casino.
"This was not a terrorist attack, it was not a bomb," Prague's deputy mayor, Rudolf Blazek, told reporters at the scene.
Mr Blazek said information so far showed a person threw a grenade near a casino in the tourist-filled area, but that it
rolled under a car before exploding.
The BBC's Rob Cameron in Prague said there was speculation the attack could have been the work of an organised crime gang settling scores with its rivals.
Czech Prime Minister Stanislav Gross toured the blast area. He said: "It is important to realise that this was
a criminal act related to the underworld".
There is a lucrative trade in flying gamblers from Israel, where gambling is illegal, to casinos in eastern Europe and there have been clashes in the past between gangs fighting over the business.
In August 2002, the former owner of the casino, Felix Abutbul, was shot dead in Prague.
His son, Assi, is understood to have inherited his casino business and was possibly the target of the attack, our correspondent says.