TEHRAN, Iran (AP) — Iranian leaders are defiant in the wake of President Donald Trump’s decision to impose sanctions on countries that import Iranian oil, vowing to respond to America’s move.

The U.S. announced the sanctions in November but some countries got temporary waivers that allowed them to import Iranian oil. Washington now says those waivers — which primarily impact China, India, Japan, South Korea and Turkey — will expire May 2.

President Hassan Rouhani said in comments on his website Wednesday that for Iranians, “there is no way except resistance.”

Supreme Leader Ayatollah Ali Khamenei says U.S. efforts will not bear any fruit and that Iranians are “able to export our oil to the extent that we need and when we decide.”

Khamenei also says this U.S. policy won’t “remain without an answer.”