President-elect Donald Trump is considering declaring a national economic emergency to implement his sweeping tariff policies, four sources familiar with the matter told CNN.

A declaration of this kind will give Trump the power to create the tariff program that he made the highlight of his campaign for the White House with the International Economic Emergency Powers Act, CNN reported. Also known as IEEPA, the law allows the president to monitor imports during times of national crisis.

Stock futures weakened after the CNN report and the U.S. dollar strengthened against most other currencies.

CNN sources noted that no final decision has been made on whether Trump will declare a national emergency. According to CNN reporting, Trump’s team is also examining alternative legal arguments, such as reference to certain sections of US trade law.

Trump frequently brought up import tariffs during the election campaign and at times called for levies of 60% or more on Chinese products. Weeks after his victory, the Republican promised to increase tariffs on Chinese imports by 10% and impose 25% tariffs on products from Canada or Mexico.

The Washington Post reported Monday that Trump would narrow the focus of his tariffs, an approach that Wall Street appears to favor. But the president-elect later denied this report.

Read CNN’s full story here.