PHOENIX — An environmental group and an Arizona congressman have sued to block the construction of President Trump’s wall along the southern border, threatening to derail one of his marquee projects well before it gets off the ground.

The Center for Biological Diversity and Representative Raúl M. Grijalva, the ranking Democrat on the House Committee on Natural Resources, claimed in a federal lawsuit filed Wednesday in Tucson that the Trump administration had failed to study the wall’s environmental impact before gearing up for its construction.

Mr. Trump’s plan to strengthen the border includes the hiring of 5,000 Border Patrol agents, increasing by 25 percent the ranks of the largest law enforcement agency in the country.

The lawsuit seeks to stop any work until the government agrees to analyze the impact of construction, noise, light and other changes to the landscape on rivers, plants and endangered species — including jaguars, Sonoran pronghorns and ocelots — and also on border residents.