WASHINGTON, (AP):- The United Arab Emirates on Monday said it came under attack by Iran for the first time since a fragile ceasefire took hold in early April. Authorities in the eastern emirate of Fujairah said an Iranian drone sparked a fire at a key oil facility, and the British military reported two cargo vessels ablaze off the UAE.

The attacks appeared to be in response to U.S. President Donald Trump’s latest efforts to reopen the Strait of Hormuz. U.S. forces on Monday began offering to guide commercial ships through the critical waterway and reported that two American-flagged merchant ships had successfully transited. Hundreds of ships have been stuck in the strait since the war began.

Trump on Saturday said he was reviewing a new Iranian proposal to end the war but expressed skepticism that it would lead to a deal. Two semiofficial Iranian news outlets believed to be close to Iran’s paramilitary Revolutionary Guard said Iran sent a 14-point proposal via Pakistan in response to a nine-point U.S. proposal.

Trump, meanwhile, also claimed that the war has been “terminated” because of the ceasefire — an interpretation that would allow him to skirt the War Powers Resolution, which requires Congress to authorize military action that extends beyond 60 days. Trump called this law “unconstitutional,” and its May 1 deadline passed without action after lawmakers left town.