The State Department announced Friday that at least one American was killed and one injured in the attacks in Spain, The Associated Press reports.
Two Italians were the first named victims of Thursday's terror attack in Barcelona.
Italy's Prime Minister Paolo Gentiloni said on Twitter that Bruno Gulotta, a father-of-two, and Luca Russo were among the 13 killed after a vehicle mowed down crowds of people on Las Ramblas, a pedestrianized thoroughfare in the heart of the city, on Thursday.
Gulotta was on holiday with his partner Martina and two children, five-year-old son Alessandro and daughter Aria, who is a few months old, according to his employer.
"Yesterday afternoon in Barcelona the terrorists killed friend and colleague Bruno Gulotta," his employer, Tom's Hardware Italia, said in a statement Friday. "Today is a day of mourning."
Roberto Buonanno, the manager of Tom's Hardware Italia, said: "Little Alessandro ... is getting ready to start primary school knowing that his life and the life of his family will never be the same. And [our thoughts go to] little Aria, that [she] does not see the terrible scene in her eyes, but will never know her father".
According to his LinkedIn profile, Gulotta lived in Milan, Italy.
Citizens from at least 34 countries are among the 14 dead and more than 100 injured in the attacks in Barcelona and the coastal town of Cambrils, according to officials.
Early on Friday, five armed attackers wearing fake explosive belts drove through a crowd of people in Cambrils, killing one woman. Police killed all five attackers in a shootout.
Twenty-six French citizens have been injured, with at least 11 in a serious condition, the French Foreign Affairs Ministry said in a statement.
Thirteen German nationals were injured and hospitalized, ''some seriously and still fighting for their lives,'' Foreign Ministry spokesman Martin Schaefer announced Friday.
The Australian government has said four of its citizens were hurt -- two men have been discharged from hospital, while two women were in serious but stable condition.
Two people from Taiwan were severely injured and were undergoing emergency treatment, according to the China's Ministry of Foreign Affairs.
Four Irish citizens of Filipino descent were injured, said the Foreign Affairs office in the Philippines, while the Peruvian consul in Barcelona confirmed one of its citizens was injured but not seriously so.
More to follow.