Police in the Czech Republic are investigating a fire that killed 11 people, including three children.
The deputy mayor of the north-eastern town of Bohumin said the apparent arson attack was the result of family dispute.
Six people died in Saturday's blaze and another five were killed after jumping from an 11th floor balcony in an attempt to escape the flames.
Ten people, including two firemen and a police officer, were injured.
Bohumin is on the Czech-Polish border, some 300km (190 miles) east of the capital, Prague.
According to eyewitness reports, a man was handcuffed at the scene after calmly admitting to police he had started the blaze.
Police refused to comment on those claims but they have confirmed that one person was arrested.
Deputy Mayor Igor Bruzl told Czech Television that the family who lived in the flat had been resident in the municipally-owned block for some time.
He denied that a dispute with neighbours was the cause of the fire and also rejected reports that there was an ethnic dimension to the case.
Mr Bruzl said he knew the identity of the man arrested but could not comment further, only adding that he was related to the residents in the flat.
The regional fire brigade chief Vladimir Vlcek told Czech Television that the blaze spread very quickly.
"The fire was very quick to develop, which is not normal. A fire like that typically affects one room, but this one hit the entire flat, all the rooms are burnt down,"
Unconfirmed local reports say the suspect had entered the flat, where a large family celebration was taking place, and poured petrol around the rooms before setting it alight.