In a ruling Friday night, a federal judge blocked a new Seattle law prohibiting police from using pepper spray and other anti-riot weapons.

The new law was set to take effect Sunday but U.S. District Judge James Robart granted a request by the federal government to block the measure, the Seattle Times reported.

The Seattle City Council passed the new law unanimously last month, hoping to reduce violent clashes between police and protesters.

SEATTLE MEDIA MUST PROVIDE UNPUBLISHED PROTEST VIDEOS AND PHOTOS TO POLICE, JUDGE RULES

But the U.S. Justice Department argued that the inability to use pepper spray, blast balls and other devices might actually lead to more police use of force, not less, the Times reported.

Seattle police officers hold weapons as they stand guard outside the East Precinct Building recently. (Associated Press)

In his ruling, Robart determined that the situation required further discussion between the city and the Justice Department, which years ago entered a settlement agreement regarding a police department overhaul because of past complaints about excessive force and biased policing.

Robart called his restraining order blocking the law “very temporary,” and advised the city and the Justice Department to engage in constructive discussions regarding the next step.

“I urge you all to use it as an occasion to try to find out where it is we are and where it is we’re going,” he said, according to the Times. “I can’t tell youy today if blast balls are a good idea or a bad idea, but I know that sometime a long time ago I approved them.”

Prior to the judge’s Friday ruling, Seattle police Chief Carmen Best, in anticipation of the new law taking effect Sunday, announced plans for “adjusted deployment” methods that she said were designed to protect police officers who would lack access to the anti-riot weapons.

But the judge’s Friday ruling move the chief’s plans moot – at least for now.

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Meanwhile, on Thursday, a federal government plan arrived in Seattle, carrying federal law enforcement officers who were expected to be deployed this weekend to protect federal buildings from any possible rioting.

They would augment the deployment of local police.

Robart is the presiding judge in the 2012 consent decree that required Seattle city officials to address the past allegations of excessive force and biased policing.

Fox News’ Caitlin McFall, David Aaro and The Associated Press contributed to this story.