Officers detained two pairs of brothers, Spaniards of Moroccan origin, in the Spanish territory of Ceuta bordering Morocco, the interior ministry said in a statement.
It said they had "a very similar profile" to the killers in this month's Islamist
Interior Minister Jorge Fernandez Diaz compared the suspects to the two brothers -- Cherif and Said Kouachi-- who killed 12 people in an attack on the Paris offices of the French satirical magazine Charlie Hebdo.
The Ceuta suspects resembled the Paris attackers in their "physical and psychological preparation and their skill in using weapons", he told reporters.
The Spanish suspects also had a "firm determination...
The Ceuta four
"They formed part of a
It did not say whether the four had made any concrete plans for an
Police seized a nine-
The four suspects were to be flown by helicopter to
On alert after Paris attacks
They were the latest in a string of arrests in Ceuta and Spain's other north African territory, Melilla, where authorities have been monitoring suspected extremist cells.
In recent weeks the Paris attacks have put Spanish police on heightened alert for extremists on their soil.
They are helping investigate suspects linked to the attacks in Paris and other plots that were foiled later in Belgium, who are said to have earlier travelled to Spain.
Spanish counterterrorism sources said a third gunman behind the Paris attacks, Amedy Coulibaly, drove five people to Madrid in early January, before the attacks, to catch a plane to Turkey.
Belgian authorities have
Spanish police have arrested about 50 suspected
Some were caught after returning from zones controlled by the
That has raised concerns over "homegrown" and "lone wolf" extremists -- a familiar trend in Britain, France and Germany where hundreds of
The Spanish government
Spain suffered one of Europe's worst ever peacetime attacks on March 11, 2004, when Al-Qaeda-inspired bombings killed 191 people in an attack on Madrid commuter trains.