Spain's hunt for the driver of a van that barreled through a Barcelona crowd last week focused Sunday on the northeastern towns of Ripoll and Manlleu.
Police set up numerous roadblocks hoping to snare Younes Abouyaaquoub, a 22-year-old Moroccan man they suspect was behind Thursday's attack, which killed 13 people and injured more than 100 others.
In a news conference Sunday, Spanish police also reported that they had found 120 gas canisters in a home believed to be the bomb-making factory of the suspects in Thursday's attacks. Enough materials were found to carry out "one or more attacks in Barcelona," regional police chief Josep Lluis Trapero told reporters, revealing that traces of TATP explosive had also been found.
In addition to Abouyaaqoub, two other suspects are being sought, including an imam named Abdelbaki Es Satty. Authorities believe Es Satty may have radicalized some of those who carried out the attacks.
Police already have four people in custody they believe are connected to the attacks.
Investigators are trying to determine if some of the suspects sought were killed Wednesday night in an explosion that leveled a home in Alcanar. Human remains were found in the rubble left by the blast, which police believe may have been caused by mishandling butane canisters that were intended to be used in an attack. DNA testing is underway to determine how many people died in the explosion.
The Associated Press reports that neighbors said the vehicles used in the Cambrils and Barcelona attacks were seen at the Alcanar home prior to the blast.
Police said a seven-year-old boy with dual Australian and British citizenship has been identified as one of the victims, along with an Italian and a Belgian, but did not reveal their names.
On Sunday Spain's King Felipe VI and Queen Letizia, along with Prime Minister Mariano Rajoy, attended a mass for the victims of the attacks at Barcelona's Sagrada Familia Basilica.
During the service, the archbishop of Barcelona read a telegram of sent by Pope Francis, who called the attacks a "cruel terrorist act" and a "grave offense to God."
The king and queen visited victims in hospitals on Saturday and placed a wreath and candles at the site of the Barcelona attack.