MADRID - Security forces have broken up a Spanish and Moroccan network suspected of sending jihadist fighters to battle Syrian President Bashar al-Assad's regime, arresting seven suspects, Madrid said on Friday.
Spain's government said it was the "most important" cell it had detected sending jihadists to Syria and other conflict zones.
"The operation is still ongoing," Spain's interior ministry said in a statement.
Security forces arrested four of the suspects in Spain, including the head of the network, and another three in Morocco, the ministry said.
Of the suspects caught in Spain, one was snatched in Malaga and the other three in Melilla, one of two Spanish-held cities on the northern Morocco coast, it said.
Further details were not immediately available.
Spanish security forces fear battle-hardened Islamist fighters may return from Syria to Spain while still under the influence of Al-Qaeda-inspired groups, presenting a grave threat.
Just three days before the latest arrests, Spain marked the 10th anniversary of an Al-Qaeda-inspired bombing of four packed commuter trains in Madrid, which killed 191 people.
Spain's Interior Minister Jorge Fernandez Diaz warned on the eve of the anniversary that Islamist extremists remained a threat.
Al-Qaeda's leaders and its affiliates, including the north African group Al-Qaeda in the Islamic Maghreb and armed Islamists fighting in Syria, refer frequently in their statements to "Al Andalus" in reference to Spain, he said.
"Clearly Spain forms part of the strategic objectives of global jihad. We are not the only ones but we are in their sights obviously," Fernandez Diaz said.
Since the Madrid train bombings, 472 suspected Islamic extremists have been arrested in Spain, he said.
Some 1,800 Spanish police and counter-terrorist security forces, in addition to the intelligence service, are now grappling with the threat of a new attack, the minister said.
The Spanish counter-terrorist service's alert system is at its second-highest level, signifying "a likely risk of attack", a level that has not changed in recent years.