ANKARA, May 8 (Xinhua) -- Turkey's Foreign Ministry slammed on Tuesday Washington's decision to withdraw from the Iran nuclear deal as "an unfortunate step."

The Joint Comprehensive Plan of Action (JCPOA) accepted in 2015 was an important step taken to prevent proliferation, the ministry said in a written statement.

"Turkey has always defended the stance that Iran's nuclear program should be resolved through diplomacy and negotiations and has made intensive efforts in this direction," it added.

Turkish Presidential Spokesman Ibrahim Kalin criticized that U.S. unilateral withdrawal from the deal will cause instability and new conflicts.

"Turkey will maintain its resolute stance against all forms of nuclear weapons," Kalin said on his Twitter account.

U.S. President Donald Trump announced Tuesday the U.S. will pull out of the landmark nuclear agreement in 2015, vowing to re-impose nuclear-related economic penalties on Iran.