Brussels (AFP) - Belgium on Saturday deployed troops to patrol its streets after smashing an Islamist "terrorist" cell that allegedly planned to kill police officers, as Greece arrested four people in connection with the foiled plot.
Abdelhamid Abaaoud, the 27-year-old suspected mastermind of the dismantled cell was thought to be among those detained by anti-terror police in Athens, but it could not be immediately confirmed.
To formally identify the Belgian of Moroccan descent, Greece has to send digital fingerprints and DNA samples to the Belgian authorities, a Greek police source said. Belgian prosecutors declined to comment when contacted by AFP.
The arrests took place in the Pangrati district of the Greek capital, the source said. Several mobile phones were also seized.
The arrests come after Belgian security forces killed two suspected Islamists in a huge anti-terror raid in the eastern town of Verviers Thursday, disrupting a suspected plan to attack police in the country.
With tensions heightened, some 150 soldiers took up positions in the northern Belgian town of Antwerp, notably to protect jewellers and a large concentration of Orthodox Jews.
The NATO headquarters, various EU offices and the US and Israeli embassies are also in the area, as well as Brussels' main synagogue, said Defence Minister Steven Vandeput.
Antwerp has a large Jewish population.
"The mobilised troops will be armed and their primary responsibility will be to survey certain sites" and to reinforce police, Prime Minister Charles Michel's office said in a statement.
Outside the Jewish Museum of Brussels, where a jihadist attacker killed four people in May 2014, armed soldiers stood watch.
Up to 300 troops may be deployed in what would be the biggest operation since the terrorist bombings carried out by the Communist Combatant Cells of the mid-1980s.
The Belgian raid came a week after Islamist attacks in and around Paris killed 17 people, rekindling fears in Europe about the threat posed by young Europeans returning home after fighting alongside extremist groups in the Middle East.
- Alleged ringleader -
According to Belgian media, alleged ringleader Abaaoud, who spent time fighting alongside the Islamic State group in Syria, may have led and financed the dismantled jihadist cell from Greece.
Abaaoud was already known to security forces after appearing in a video from the Islamic State group in which he can be seen driving a car dragging dead bodies.
He is also known as the older brother of a 13-year-old boy dubbed Syria's youngest foreign fighter by British media after photos surfaced of him posing with weapons.
Following the raid in Verviers, Belgian police arrested 13 people across Belgium, five of whom were later charged with "participating in the activities of a terrorist group."
Weapons, bomb-making materials, police uniforms and fake documents were found during searches of their homes.
Belgian prosecutors said there were no immediate links with last week's Islamist attacks in Paris on the Charlie Hebdo satirical magazine, a Jewish supermarket and a policewoman, the country's worst attacks in half a century.
Two fugitives who left Belgium immediately after the attack have been arrested in the French Alps.
Belgium estimates that 335 of its people have gone to fight in Syria and Iraq in the last few years -- putting it top of the list of European nations in proportion to its small population of 11 million.
Of the 335 who have gone to fight, some 184 are still there and 50 have been killed, while 101 have returned to Belgium.