Turkey "strongly condemned this heinous attack" according to a Foreign Ministry statement.
"Turkey and the Turkish people, who have been the target of several similar attacks, share the grief of Sweden and the Swedish people," the ministry said.
UN Secretary-General Antonio Guterres also condemned the attack, saying his organization stood "in solidarity with the people and government of Sweden".
At least three people were reported killed when a stolen truck drove into a large department store in Drottninggatan Street, central Stockholm.
Swedish Prime Minister Stefan Lofven later said evidence pointed to what he described as a "terror attack."
Swedish media also reported gunshots in the area.
All metro stations were closed and the public was called upon to keep away from the city center.
Friday's incident follows a number of similar attacks across Europe where vehicles have been used as weapons, being driven into crowds of pedestrians.
Over 80 people died after a terrorist drove a truck into French crowds celebrating Bastille Day last July in the southern city of Nice.
More recently, 12 people lost their lives in Berlin when a truck rammed into shoppers at a Christmas market in the German capital.
Just over two weeks ago, five people died in a terror attack outside the U.K. parliament in London. The killer used a car to ram into pedestrians crossing Westminster Bridge.