President Donald Trump on Thursday warned Iran it must strike a deal on its nuclear program within 10 to 15 days or face “really bad things,” prompting Tehran to threaten retaliation against US bases across the Middle East if it is attacked.

Trump Cites Airstrikes, Sets Tense 15-Day Deadline

According to Reuters, speaking at the first meeting of his newly created Board of Peace in Washington, Trump said talks with Iran were “going well” but demanded a “meaningful” agreement as the United States rushes additional forces into the region, raising fears of a wider war. “Otherwise bad things happen,” he said, repeating a threat he has made throughout his renewed “maximum pressure” campaign.

Trump pointed to US and Israeli airstrikes last June that he said had “decimated” Iran’s nuclear potential, and suggested further action could be coming. “We may have to take it a step further or we may not,” he told the gathering. Later, aboard Air Force One, he said 10 to 15 days should be “pretty much maximum” for Iran to decide but declined to spell out consequences beyond warning again of “really bad things.”

Iran Vows Retaliation As Markets Grow Jittery

The standoff has already rattled global markets. Oil prices have climbed on expectations of possible disruption to shipments through the Gulf of Oman, where a Russian corvette on Thursday joined planned Iranian naval drills along a key energy route.

Diplomats Juggle Nuclear Talks Amid Military Buildup

Iran maintains its nuclear activities are for peaceful energy purposes and says it will not accept limits beyond the atomic file, including on its missile arsenal and regional allies. The United States and Israel, citing years of intelligence and Iran’s enrichment of uranium to levels near weapons-grade, accuse Tehran of seeking the capability to build a bomb, a charge Iran denies.

Meanwhile, Trump has sent aircraft carriers, warships and jet squadrons to the region while satellite imagery shows both Iranian efforts to harden nuclear and missile sites and US preparations at bases across the Middle East.

U.S. stock futures climbed higher during overnight trading on Thursday. Futures of all the major benchmark indices were higher at the time of writing. The S&P 500 futures were up 0.17%, trading at 6,888.75; Nasdaq futures were up 0.20%, at 24,907.75; and the Dow Jones futures were trading at 49,505, up 0.10%.

Image via Shutterstock/ Joey Sussman