At midnight in Paris, the Eiffel Tower went dark to mourn the lives lost during Fridays suspected terrorist attack in Swedens capital.

At least four people were killed and more than a dozen injured after a vehicledrove into a crowd of peopleat a shopping district in Stockholm.

Sweden has been attacked, Prime Minister Stefan told news reporters on Friday. Everything points to the fact that this is a terrorist attack.

This is the second time this week the Eiffel Tower has shut off its lights to show respect and solidarity with a country reeling from tragedy.The tower went dark Tuesday in response to an explosion thatkilled 14 people and injured 50 others in a subway in St. Petersburg, Russia.

Paris Mayor Anne HidalgocalledFriday for the Eiffel Towers lights to be switched off earlier than scheduled.

Horror struck Sweden at its heart today, Hidalgo tweeted. All my sympathy goes to the victims and their families.

The Eiffel Towers lights are typicallyturned off every night at 1 a.m., according to the towers website. But sometimes the lights are shut down earlier in recognition of a terrorist attack or to raise awareness of various issues.

When a terrorist rammed pedestrians with his vehicle and stabbed a guard in London last month, Paris shut off the Eiffel Towers lights at midnight in honor of those killed. The lights were turned off at 8 p.m. Dec. 14 to call attention to the humanitarian crisis in Syriaand in 2015 to mourn the victims of the Charlie Hebdo attack in Paris.