PHOENIX — The federal government is delaying construction on parts of the border fence in Arizona because it's still working on design plans.

Attorneys said in a court filing late Tuesday that plans to replace waist-high barriers this month with taller fencing in a wildlife refuge, national monument and conservation area are being delayed until October.

Authorities plan on using Defense Department funds under President Donald Trump's emergency declaration.

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The Center for Biological Diversity last week asked a federal judge to halt work on 68 miles (109 kilometers) of border wall, saying the government unlawfully waived dozens of laws. 

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Environmentalists say the new barriers will damage wildlife habitat.

The government says the replacement fencing is crucial to national security.

It will proceed with construction on a two-mile stretch near an official border crossing beginning next week.

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