TEHRAN, Iran (AP) — Iran’s Revolutionary Guard said Thursday it shot down a U.S. drone amid heightened tensions between Tehran and Washington over its collapsing nuclear deal. The U.S. military declined to immediately comment.

The reported shootdown of the RQ-4 Global Hawk comes after the U.S. military previously alleged Iran fired a missile at another drone last week that responded to the attack on two oil tankers near the Gulf of Oman. The U.S. blames Iran for the attack on the ships, which Tehran denies.

The attacks come against the backdrop of heightened tensions between the U.S. and Iran following President Donald Trump’s decision to withdraw from Tehran’s nuclear deal with world powers a year ago. The White House separately said it was aware of reports of a missile strike on Saudi Arabia amid a campaign targeting the kingdom by Yemen’s Iranian-allied Houthi rebels.