The number of firebombing incidents in the Netherlands is increasing and there have been 250 so far this year, broadcaster NOS said on Friday.

The latest explosion involving powerful fireworks took place outside the house of a  plumber in Vlaardingen on Wednesday. His home has been targeted regularly for the past few months.

Last year, police were called out 900 times to attacks and attempted attacks involving firebombs, updated police figures show.

Most explosions take place in the Rotterdam and Amsterdam regions, and appear to be related to conflicts between drug gangs, although police think some are down to copycat behaviour. Firebombing has also been a feature of conflicts between neighbours and (business) partners, police said.

None of the people targeted have been hurt. A 23-year-old man, thought to be the firebomber, died in the attempt at an incident in The Hague in January.

The perpetrators are often youngsters, some no more than teenagers. Police arrested a 13-year-old for his involvement in a firebombing incident at a house in Medemblik on Thursday and a 14-year-old and a 15-year-old were picked up earlier this week in connection with the incident.

Despite successful efforts to track down perpetrators, the number of attacks continues to grow because criminals find new recruits to do their dirty work while they stay under the radar, police said. Six different young firebombers have been arrested in the Vlaardingen case but the attacks keep coming.

Police, the public prosecution office and mayors are in talks about a common approach to the incidents which may also involve a campaign to stop young people from carrying out the attacks.

Some local councils, such as Vlaardingen, are running out of options as costs for camera surveillance are mounting and there is not enough police capacity to guarantee the safety of the other people living in the street. The mayor has since ordered the plumber to leave his home and move elsewhere for the third time.

The Hague has been using 23 moveable surveillance cameras but the number of explosions in the city doubled last year. “This is a complex problem and there is no quick and simple solution,” mayor Jan Van Zanen said in a recent letter to the council.