Spanish police on Tuesday arrested four men with alleged links to suspects held in Belgium over their involvement in the Brussels airport and metro attacks last year, officials said.
The four were among nine men arrested in a vast operation targeting suspected Islamic extremists that was carried out in the northeastern region of Catalonia in conjunction with Belgian police, Catalan police said in a statement.
The men — a Spanish national and eight Moroccans living in Catalonia, all 30 to 40 years old — are believed to belong to a terrorist organisation, the statement added.
"Four of those who were detained have links with people arrested for the attacks carried out at Brussels airport and metro," a spokesman for Catalonia's regional police force told AFP.
It is not clear if the four were directly involved in carrying out the Brussels attacks, the spokesman added.
Belgium has been on high alert since March 22 last year when suicide bombers attacked Zaventem airport and the Maalbeek metro station, killing 32 people and leaving more than 320 wounded.
The attacks were led by an Islamic State cell that was also responsible for the carnage in Paris in November 2015.
"The Belgian judge leading the investigation into the Brussels airport attack found ties between the suspected authors of the attack and the Moroccans who live in Catalonia," a spokesman for Spain's National Court, which handles terrorism investigations, told AFP.
The men arrested in Catalonia "may have participated or cooperated in past actions" and may have travelled to Belgium, Catalonia's regional interior minister Jordi Jane told radio Rac1.
There were no "clear indications" that the suspects arrested Tuesday intended to carry out an attack in Spain, he added.
The authorities said the suspects were also being investigated for drug trafficking, robbery and other crimes.
Most of the nine men arrested Tuesday have criminal records related to petty or organised crime, police said.
Police raided 12 properties in six Catalan cities, including the regional capital Barcelona, as part of the operation which followed an eight-month investigation.
Officers seized three firearms, drugs, cash and electronics during the dawn raids.
At the same time, police in Morocco searched several homes of family members of the suspects arrested in Spain. They were accompanied by Spanish police.
Between 2012 and October 2016, Spain detained 186 people with suspected links to Islamic jihadism, including 63 in Catalonia, according to the interior ministry.
Spain, the world's third most visited country, increased its terror alert to category four on a five-point scale in 2015 after attacks in France, Tunisia and Kuwait.
The country has been mentioned on extremist websites as a possible target for historical reasons, since much of its territory was under Muslim rule from 711 to 1492.
But it has been spared major jihadist violence since March 2004, when bombs exploded on commuter trains in Madrid, killing 191 people in an attack claimed by Qaeda-inspired militants.
Unlike France or Belgium, Spain is less exposed to the risk that radicalised citizens who left to fight abroad will return with plans to commit attacks on home soil.
Only around 160 Spaniards are estimated to have joined the Islamic State group in Iraq and Syria, according to a study by the Real Instituto Elcano think tank, compared with over a thousand from nearby France since 2012.
Updated Date: Apr 25, 2017 20:16 PM