Bordeaux (AFP) – Fears over their fans and the fitness of Luka Modric have overshadowed Croatia’s preparations for their bid to secure a last 16 place at Euro 2016 against two-time defending European champions Spain on Tuesday.

The Croatian football federation were fined 100,000 euros ($113,000) on Monday after flares were lobbed onto the Saint-Etienne pitch during the 2-2 draw with the Czech Republic on Friday.

The disturbances sparked outrage in the Balkan nation. Coach Ante Cacic branded the perpetrators “sports terrorists”.

Hardcore supporters of Croatian club Hajduk Split have threatened on Facebook to also disrupt the Spain game.

However, Cacic is hopeful for a more peaceful evening thanks to reinforced security measures.

“I’m not too worried, the organisers and French police can be more prepared and try to fix all these problems,” he said on Monday.

Spain defender Gerard Pique also called on Croatian fans to allow the players to be the protagonists in a tournament marked by persistent crowd trouble.

“We understand football is a spectacle, we understand it is a show for the fans,” said the Barcelona defender.

“We don’t accept any kind of violence in football and I hope all the fans can respect this game, the players and the other fans who enjoy watching the game.

“Think about the kids the families in the stadium. These events cannot be repeated and I hope for the good of footballl this all ends and never happens again.”

On top of their off-field problems, Croatia could be without key man Modric.

The playmaker limped off against the Czechs, when his side were leading 2-0.

– Serene Spain –

“Modric had a scan, there is no rupture of the muscle so I will decide after tonight’s training session whether he will play,” added Cacic.

Modric’s teammate Ivan Perisic hinted he will be rested to ensure he is fit for the knockout stage.

“We all know how good Luka is,” said the Inter Milan winger.

“Maybe it is better he doesn’t take risks tomorrow against Spain because we will need him for the next matches.”

Spain’s scintillating start has seen them already secure their place in the last 16 and strengthen their standing among the tournament favourites.

Vicente del Bosque’s men needed a late Pique header to see off the Czechs in their opening game before an Andres Iniesta-inspired a 3-0 thrashing of Turkey.

Their serene progress was rocked slightly when winger Pedro Rodriguez claimed Monday he could retire from international football at just 28 after becoming frustrated with his secondary role.

Pedro has played just eight minutes in one substitute appearance in Spain’s opening two matches.

“It is difficult to assume this role for me. If you don’t play it isn’t worth it coming just to make up the numbers,” he told Spanish broadcaster Movistar.

However, Pique and Del Bosque tried to play down suggestions of disharmony in the Spanish camp.

“You journalists get bored and treat the Pedro thing like the biggest thing ever,” said Pique.

“We try to make sure everyone is happy, but it is inevitable that at some moment the 12 that don’t play won’t be happy,” added Del Bosque.

Spain still need a point to make sure of top spot in Group D and in theory a place on the easier side of the draw for the knockout stage.

However, Del Bosque is expected to make up to four changes.

Sergio Ramos, captain for the opening two games, is likely to be one of those rested. He is just one yellow card away from a suspension.

In the other group game in Lens, the Czech Republic and Turkey have to win to maintain their hopes of progressing to the knockout stage.

Pavel Vrba’s Czechs could even steal second place from Croatia with a win allied to a Spain victory.

Milan Skoda and Tomas Necid are in contention to start after coming off the bench to score against Croatia.

Turkey need a big win to have any chance of qualifying as one of the four best third-placed sides.

Coach Fatih Terim is set to keep faith with Barcelona’s Arda Turan despite the midfielder being booed by his own fans for his poor display against Spain.