Police officers work on a street in Verviers, Belgium, on Thursday. (Associated Press)
Belgium was on high alert today after two suspected jihadists were killed in a police raid, while German and French police made fresh arrests to put Europe on edge a week after the Islamist attacks in Paris.
The series of raids across the continent highlighted fears about young Europeans travelling to fight holy war with the Islamic State and other extremist groups in the Middle East, and then returning to launch attacks on western targets.
In Belgium, officials said they had averted "imminent" large-scale attacks on police targets after raiding a terror cell in the eastern town of Verviers, near the German border, whose members had recently come back from Syria.
Police shot dead the two suspects in a gun battle after they opened fire on officers with heavy weapons, and arrested a third man, while there were several search operations in Brussels and its suburbs.
Belgian Prime Minister Charles Michel raised Belgium's terror alert to its second highest level, security was tightened and Jewish schools in the port city of Antwerp closed today due to fears of further trouble.
The raid and a series of related search operations across Belgium were now "over" but authorities were now seeking to "exploit the information" they had obtained, Foreign Minister Didier Reynders said.
"The threat was to the police forces," he said of the planned attacks.European fears
Europe has been on alert since the Islamist attacks on the French Charlie Hebdo satirical magazine, which printed cartoons of the Prophet Mohammed, and a Jewish supermarket in Paris last week in which 17 people were killed.
With France still reeling from the attacks which targeted its cherished traditions of free speech, US Secretary of State John Kerry was to lay wreaths on today at both the magazine's offices and the grocery during a visit to Paris.
It follows criticism of the US for not sending a top representative to a march in Paris on Sunday, which drew 1.5 million people and dozens of world leaders in the wake of the attacks.
The funeral of Stephane Charbonnier, alias Charb, the Editor-in-Chief of Charlie Hebdo, was also due to take place on today.
Police in France meanwhile detained 12 people overnight in the suburbs of Paris in connection with the attacks, carried out by Islamist brothers Said and Cherif Kouachi and Amedy Coulibaly.
The nine men and three women were to be questioned about "possible logistic support" they may have given to the gunmen, in particular weapons and vehicles, the source said.
In Germany an alleged leader of a group planning to carry out an attack in Syria was arrested in raids on suspected Islamist sites in and around Berlin by more than 200 police officers, officials said.
The arrested man is a 41-year-old man of Turkish origin and is suspected of "leading an Islamist extremist group made up of Turkish and Russian nationals from (the Caucasus regions' of) Chechnya and Dagestan," the police said in a statement, adding that "there is no indication that the group was preparing attacks inside Germany."Belgium links probed
While there were no direct links between the arrests across the three neighbouring countries, it came on the heels of calls for greater anti-terror cooperation across the EU.
Belgian prosecutors said they had found "no link at this stage" to the Paris attacks but earlier said they suspected a Belgian man could have supplied Jewish supermarket gunman Coulibaly with his weapons.
The suspect, Neetin Karasular, had bought a car belonging to Coulibaly's partner Hayat Boumeddiene, who has since fled France, apparently reaching Syria. He handed himself in to police on Tuesday.
Belgium has one of the largest number of extremists who have returned from Syria relative to its population, with a large Muslim community that suffers from high unemployment and disenfranchisement.
Belgium was also the first country to suffer an attack by a suspected former Syria fighter after four people were shot dead at the Brussels Jewish museum in May 2014. Frenchman Mehdi Nemmouche has been charged with murder.
The verdict in a major trial of an Islamist group, Sharia4Belgium, accused of sending young Belgian fighters to Syria is due to be delivered next month.