Moroccans and a Spaniard
A property in Ripoll where two brothers implicated in the attacks were resident. Photo: AFP
The suspects are all youths -- most of them Moroccans who lived in Ripoll, a town in Spain's northeastern Catalonia region where both of the attack sites were also located.
Police have launched a manhunt for Younes Abouyaaqoub, a 22-year-old born in Mrit in central Morocco -- without confirming reports that he was the driver who smashed a van into a crowd in Barcelona on Thursday, killing 13 people and injuring dozens of others.
Police have also released the identities of three of five suspects shot dead early Friday by security forces after a second ramming attack in the seaside resort of Cambrils that left one person dead and six others injured.
Mousa Oukabir, 17, was born in Ripoll but has Moroccan citizenship. He lived in the same building as Mohamed Hychami, 24, who was from Mrit. Said Aallaa, 18, was from the Moroccan village of Naour.
In addition, four men -- three Moroccans and a Spaniard aged 21 to 34 -- have been arrested in connection with the attacks. These include Driss Oukabir, the older brother of Moussa Oukabir.
Another of the arrested suspects is a Spanish national in Melilla, a Spanish territory in North Africa.
Ripoll, in the foothills of the Pyrenees, is home to about 10,000 people, including 1,200 foreigners.
Raised in Catalonia
Most of the suspects accused of involvement in the carnage, which has been claimed by the Islamic State group, had lived for a long time in Catalonia.
The wealthy region is home to Spain's largest Muslim community -- about 500,000 of the country's 1.9 million Muslims, according to the Union of Islamic Communities of Spain.
It is the Spanish region with the most arrests related to jihadism, along with Madrid and Spain's North African territories of Ceuta and Melilla.
No terrorist background
None of the suspects had been known to anti-terrorism agencies, but they did have criminal records.
Said Oukabir, the father of the Oukabir brothers, said he was "in shock" that his sons were suspected of involvement in the attacks.
His sons had shown no sign of radicalisation, he added at his home in Melouiya, a village high in Morocco's Atlas Mountains.
"They lived like the young people of their age, dressed like them," the father said.
Gas cannister plot
A policewoman at the house in Ripoll where gas bottles were stored. Photo: AFP
Police suspect that two men who were part of the cell died in a blast while trying to make explosives at a house in the town of Alcanar, about 200 kilometres (140 miles) south of Barcelona on Wednesday evening.
Police removed around 30 gas canisters from the house, which they believe were going to be used in a larger attack.
Fake suicide belts
The five suspects who were killed by police in Cambrils were wearing fake explosive belts. They were carrying knives and an axe in the car they used to plough into people.
Terrorism experts say their goal was to die as martyrs since police do not hesitate to shoot when they see suicide vests, although the attackers may have also hoped to take people hostage to buy time.
Police have seized three vehicles that were rented by the suspects and are being analysed.
Spanish police have also tipped off their French counterparts about a white van linked to the attacks that may have crossed the border, a French police source told AFP.