Democratic Attorney General Aaron Ford is joining California and 14 other states in a lawsuit challenging President Donald Trump's declaration of a national emergency to access more money for a border wall.

The states are seeking to block the declaration as well as unauthorized construction of the wall and diversion of congressionally appropriated funds. Ford had hinted last week that he might sue over the matter.

"President Trump cannot sidestep our Constitution for a political ploy," Ford said in a statement. "The Trump Administration's proposed diversion of funds would waste billions of dollars that is dedicated to supporting our military and law enforcement agencies."

Trump's declaration last week allows him to access $3.5 billion for the wall from military construction spending. He also has plans to divert $2.5 billion from the Pentagon's counternarcotics program and $600 million from the Treasury that was collected through asset forfeiture.

The moves would give Trump about $8 billion for the wall, counting the $1.4 billion he was allowed through a congressionally approved spending bill.

"They say walls don't work. Walls work 100 percent," Trump said of Democrats who have opposed a wall. "It's all a big lie. It's a big con game."

Ford's office said the declaration isn't warranted because unlawful entries at the southern border are at a 20-year low, and illegal drugs are more likely to come through official ports of entry. The states also allege that Trump's action exceeds the power of the executive office.

Ford said the funds that would be diverted toward the wall support military construction, including housing at Nevada military bases. Ford also said that diverting the money could hinder Nevada law enforcement agencies' ability to fight drug trafficking.

Along with Ford, attorneys general from California, Colorado, Connecticut, Delaware, Hawaii, Illinois, Maine, Maryland, Michigan, Minnesota, New Jersey, New Mexico, New York, Oregon and Virginia are on the complaint.