Illustrative image of a housing construction site in Tel Aviv
Authorities said a van mounted a pavement and struck several people in a "massive crash" in the area of the city that is popular with tourists.
Spanish media report two people have been killed. Carles Puigdemont also said 80 people have been hospitalized, 15 seriously.
The Catalan regional police force Mossos d'Esquadra informed of the incident, which took place in the tourist area of the Ramblas, close to Plaza de Catalunya in the heart of the city at around 17:00 local time.
An eyewitness who spoke with local police said the situation was "very tense" and all surrounding shops are being evacuated.
The area around the incident was cordoned off, with several ambulances and police vehicles on the scene, an AFP correspondent said.
According to a witness who spoke to Sky News, he heard a "crashing noise" followed by people screaming.
The terrifying scenes are similar to the ones seen in Nice, Berlin, London and Stockholm in recent months.
There were also reports that detectives believe two vans were used, one for the attack and a second as a getaway vehicle.
Korea issue with US
The chairman said the men shared some thoughts about the common challenges facing their nations, but focused mostly on North Korea.
State Reports Its 1st Human Case Of West Nile For 2017
If you have an ornamental pond, contact the Solano County Mosquito Abatement District at (707) 437-1116 for a free mosquito fish. About one in five will develop mild symptoms, including fever, headache, body aches, nausea, vomiting and swollen lymph glands.
Kenya's Raila Odinga calls strike as he mulls options
The protests were inspired by the announcement that incumbent President Uhuru Kenyatta is the victor of the Tuesday election. Raila Odinga and NASA coalition have however disputed the results terming the electoral process a charade.
Iran's Chink In The Armor: Human Rights Sanctions
Religious, military, and political leaders attended the August 3 ceremony, which was broadcast on Iranian state television. However, Iran said earlier this week that it would lodge a complaint with the commission that oversees its implementation.