Violence had continued despite a letter Platini sent to the last 16 clubs in the Champions League a fortnight ago, and there were incidents at the Euro 2008 qualifiers over the weekend, UEFA spokesman William Gaillard said.

"He's now going to write to the heads of the 53 federations to remind them of their duties, and the executive committee supports him on the watchword: zero tolerance for violence and those who are violent," Gaillard said.

UEFA are currently examining appeals against sanctions imposed after a mass brawl between Valencia and Inter Milan players in a Champions League tie on March 6. A ruling is expected shortly after the hearing on Wednesday.

Both clubs were fined 155,772 euros (207,223 dollars) and the players involved were suspended for periods ranging from two matches to seven months.

"UEFA, the associations and the clubs can do quite a lot when it comes to violence on the pitch and in stadiums," Gaillard explained.

"However, we can do less away from the stadiums -- there we need the help of the various public order authorities."

Platini and UEFA chiefs met government and police officials from several countries last week, to discuss ways to tackle violence in and around stadiums.

More meetings are due with police officials and corruption specialists.

Gaillard drew a parallel between the killing of Colombian football player Andres Escobar after the 1994 World Cup and the death of Pakistan's cricket coach Bob Woolmer, who was found strangled during cricket's World Cup last week.

"We unfortunately have violence that is generated by things outside sport -- it can be political extremism, but also corruption or illegal betting," UEFA's spokesman added.

World governing body FIFA's president Sepp Blatter warned Friday that violence on and off the pitch had driven football to a crossroads.

Blatter also raised the possibility of punishing coaches for the actions of their players.