Amsterdam— Police released all seven people arrested after an anonymous warning of a plot to plant bombs in an Amsterdam shopping district, prosecutors said Friday, easing fears that the Dutch capital was the target of a terrorist threat by Moroccan immigrants.

Police had offered no evidence to give credibility to the bomb threat, which coincided with the fifth anniversary of the deadly Madrid train bombings.

But the public prosecutors office defended the police response, which included closing a major entertainment and shopping district Thursday and arresting the suspects, all originally described as Dutch-Moroccans. The prosecutor later said at least two held only Moroccan nationality.

Spokeswoman Alexandra Oswald said the nature of the warning and information it contained had justified the action, but she did not elaborate.

After a day of interrogation and a search of locations linked to the suspects, the prosecutors office said all six men and a woman were freed for lack of evidence to support criminal allegations against them.

"No relationship with terrorist activity has been found based on statements and searches," prosecutors said in a statement late Friday.

The swift action to lock down the shopping area around the ArenA football stadium, including an IKEA furniture store and a cinema complex, reflected the nervousness the Dutch have felt since the 2004 murder of filmmaker Theo van Gogh by a Dutch-born Islamic fundamentalist angry over a short film criticizing the treatment of Muslim women.

Van Gogh's killing was followed by a spate of terrorist alerts from within the country's community of Moroccan immigrants.