The Supreme Court overturned an earlier decision that prevented the US president from using military funds to build a border wall between the US and Mexico.
The US Supreme Court temporarily ruled that President Donald Trump could use military funds to build a portion of a wall along the border of the United States and Mexico.
The court voted 5-4 to suspend a California federal judge's order to block the use of $2.5 billion (€2.2 billion) in military funds for a wall he promised to build during his campaign.
The US president celebrated the court's order, tweeting: "Wow! Big VICTORY on the Wall... Big WIN for Border Security and the Rule of Law!"
The American Civil Liberties Union, who filed the lawsuit on behalf of the environmental organisation The Sierra Club and the Southern Border Communities Coalition, said they would fight the court's "emergency stay" of the lower court ruling.
The Supreme Court is temporarily allowing Trump to access the funds, but the case will go back to an appeals court for a decision, advocacy group the Sierra Club said.
"Border communities, the environment, and our Constitution’s separation of powers will be permanently harmed should Trump get away with pillaging military funds for a xenophobic border wall Congress denied,” said Dror Ladin, staff attorney with the ACLU’s National Security Project.
The ACLU tweeted that the US president's request was a "blatant attempt to circumvent Congress's appropriation powers."
Congress, which sets the US government's budget, had previously denied Trump $5.7 billion (€5.1 billion) for the border wall which led to a 35-day partial US government shutdown.
The ACLU brought the case after Trump said after the shutdown that he would move some of the funds from the Pentagon to the Department for Homeland Security (DHS) which is responsible for border security.
The Democratic Speaker of the House, Nancy Pelosi, tweeted that the Supreme Court ruling was "deeply flawed".
The US and Guatemala signed an agreement the same day that requires migrants who arrive in Guatemala to apply to seek asylum there.