BRUSSELS -- Belgian officials have confirmed to CBS News that a suspect they want extradited from Greece may be one of the ringleaders behind the alleged plot to attack police in the European country.
CBS News correspondent Charlie D'Agata reports that, as Belgian authorities close in on the leaders of the apparent terror cell busted up last week, they've put their military on a war footing.
Hundreds of troops have begun providing high-profile protection at sites considered potential terror targets, including the U.S. Embassy, and Jewish neighborhoods.
The beefed-up security comes as foreign ministers meet in Brussels to coordinate efforts to fight the rising threat of terrorism across Europe.
Deputy Prime Minister Didier Reynders told D'Agata the troops will be around for awhile -- and not just to put people's minds at ease.
"There's a specific threat, if I may say, due to some information collected in the interventions last week," he said.
Reynders told CBS News the hunt for the ringleader in Greece originated from intercepted phone calls. They learned an attack was hours away, prompting the raids across the country last week in which two suspects were killed and a third arrested.
A U.S. official told CBS News that the suspected ringleader, a 33-year-old Algerian man, is believed to have returned from Syria and allegedly ran the operation aimed at attacking police and government officials from Greece.
In the following 24 hours, more than a dozen other people were detained for questioning across Belgium, and there have been dozens more terror arrests across Europe since the attacks in Paris that left 17 people dead.
Jittery German officials had to cancel a weekly right-wing rally against Islamic extremism after death threats to one of the so-called PEGIDA group's leaders.
With tensions running so high, parts of Europe are in lock-down. Militarized zones -- a show of force if nothing else -- have popped up in many cities in the hope of preventing further attacks.
Reynders told CBS News that among the measures foreign ministers were to discuss Monday, was the possibility of revoking passports of suspected terrorists; about as close as Europe can come collectively to setting up a no-fly list like the one in the U.S.
The Algerian man, detained Sunday on a European arrest warrant in Athens, was to go before Greek judges who were expected to rule on the Belgian extradition request within several days.