Spanish papers remain fearful of fresh terrorist attacks, despite the arrest of eight suspected Islamic militants.
The German press has plenty of advice for workers protesting against planned job cuts at one of the country's largest car manufacturers.
And a Swedish paper expresses disgust at the latest bout of football violence.
Eight suspected Islamic militants have been detained in police raids across Spain since the start of the week. For El Pais, the arrests provide a firm reminder of the attacks on Madrid's railways back in March, which left 191 people dead.
"It would be very naive," the paper suggests, "to say that the threat of Islamist terrorism has receded in Spain."
The threat, it says, "remains very serious indeed".
The profile of the men in custody, it notes, "is similar to that of the perpetrators of the Atocha atrocity".
They are "Islamic fanatics", who "prowl around the mosques", and, "in their 'hatred of the infidel', are willing to destroy anything to do with Western society".
ABC, meanwhile, is alarmed by the fact that the suspects are believed to have chosen the country's national high court as the target for an attack.
"The size and the objectives of the group give cause for concern," the paper says.
"They reflect Islamist terrorism's obsessive determination to hurt Spain."
"To face this threat," it insists, "we must mobilise all our political, judicial and security resources."
La Vanguardia welcomes the fact that the alleged plot was uncovered at an early stage.
But the paper warns that the police and the judiciary still face the difficult task "of proving that the men in custody really were plotting an attack".
"Conspiracy", it says, "provides sufficient grounds for conviction."
"But it will be difficult, if not impossible, to charge them with a crime they did not actually carry out, especially given the fact that no explosives have been found as yet."
Tens of thousands of General Motors employees in Europe protested on Tuesday at the car manufacturer's plans to cut 12,000 jobs. Germany's Der Tagesspiegel, however, questions just how much the demonstrations will actually achieve.
Workers at an Opel plant owned by the company in the German city of Bochum may feel better for taking part, the paper says, but that doesn't mean the redundancies won't happen.
"Opel is no longer Opel," it points out, "and certain products can no longer be manufactured in Germany at the same labour costs."
Management and workers alike realise companies "cannot sustain losses for years on end", it adds.
Opel employees may, however, be able to draw some consolation from the revival of another of the German motor industry's heavyweights.
"Almost bankrupt 10 years ago, Porsche is now the most profitable car manufacturer in the world," the paper notes.
Frankfurter Rundschau advises the workers to keep "a cool head" in order to strengthen their position in negotiations with company bosses.
"After all," the paper says, "management is not obliged to ask the works councils or trade unions for permission when it wants to shut down a plant."
If workers want to achieve their aim of safeguarding all production sites, protests alone are not enough, and they will have to "make compromises".
Poland's Trybuna believes the dispute over the job cuts reflects a broader trend.
"While transnational corporations are growing stronger, trade unions are growing weaker," the paper argues.
That, it says, is what is so noteworthy about "the international action of solidarity with the Opel workers" in Germany.
"Although the dismissals do not apply to Poland's Gliwice plant," it points out, "the action has spread here too."
"Were the Polish workers not to show solidarity now, they would not be able to expect the support of others in the future."
Terror on the terraces
Sweden's Dagens Nyheter wants drastic action to stamp out violence at football matches, after crowd trouble led to a 40-minute delay in the Stockholm derby between AIK and Hammarby.
"This is quite clearly an escalation of football violence to a level which we have certainly not seen before in Sweden," the paper says.
"This is not hooliganism," it argues. "This is conspiracy to commit a serious crime which would have struck innocent people - an act of terrorism."
Football clubs, the paper believes, must be held responsible for the behaviour of their fans.
It suggests they should deposit a bond with the authorities, repayable if matches are played out peacefully.
This, it maintains, would make clubs try much harder to identify and ban the culprits.
The European press review is compiled by BBC Monitoring from internet editions of the main European newspapers and some early printed editions.