DUBAI, United Arab Emirates (AP) — The U.S. military said Wednesday it has begun another round of strikes against Iran after President Donald Trump said more were coming. The escalating attacks threatened to derail efforts to end the war, with Trump warning that Tehran would “pay the price” for stalled negotiations.

U.S. Central Command said in a social media post that the military is striking “multiple targets in Iran” and that it’s being done “in response to Iran’s unwarranted and continued aggression.”

The second day of American strikes came hours after Bahrain, Kuwait and Jordan — all of which host U.S. troops — came under Iranian fire. It was the third time this week that back-and-forth strikes have tested a two-month ceasefire. They also came a day after the U.S. struck Iran following the crash of an Army helicopter near the Strait of Hormuz that Trump blamed on the Islamic Republic.

Trump urged Iran to sign a deal to end the war.

Earlier Wednesday, the U.S. military said it had fired on an oil tanker attempting to transport oil from Iran in violation of its blockade on Iranian ports.

Trump’s comments underlined his whipsaw approach to the war; earlier this week he suggested a deal to end the conflict could be reached in a matter of days.

Iran has proved resilient despite weeks of heavy bombing. It is betting that its ability to effectively close the Strait of Hormuz — a crucial passageway for oil and natural gas — gives it a strong bargaining chip.

Iran’s United Nations envoy said the U.S. should refrain from threats of force if it wants a deal.

“Iran has never negotiated under threats and pressure and will never submit to pressure or question,” Ambassador Amir Saeid Iravani told the U.N. Security Council on Wednesday.

Still, both countries seem to be looking for a way to end the conflict — if they can manage to sell it as a win at home.

Israeli Prime Minister Benjamin Netanyahu appears intent on pursuing goals that make compromise harder: the collapse of Iran’s theocratic government, the elimination of its nuclear program, and the destruction of the Iranian-allied Hezbollah militant group in Lebanon. On Monday, Iran and Israel targeted each other.