"We're going to hit them hard," Trump said, according to Fox News.
President Donald Trump announced "major combat operations" against Iran on Feb. 28, with massive joint U.S.-Israeli strikes targeting military, government and infrastructure sites.
Delegations from the U.S. and Iran entered negotiations in June aimed at a war-ending deal based on a memorandum of understanding signed by both countries.
The U.S. and Iran have nonetheless continued to exchange strikes, with the strategic Strait of Hormuz as the primary flashpoint.
Oil prices jumped on Monday morning following U.S. attacks on Iranian rocket launcher positions on Larak Island on Sunday and subsequent Iranian retaliation.
U.S. oil was trading at $86.26, up 3.44%, on Monday morning, while global oil was up 3.4% trading at $91.10.
The average price for a gallon of regular was $4.01, down 4 cents from last week's average, according to GasBuddy.
-ABC News' Victor Ordonez
Two Jordanian security sources told ABC News on Monday that some missiles targeting Jordan were not successfully intercepted, but that there were no casualties.
The sources did not specify where the missiles hit.
-ABC News' Ghazi Balkiz
The United Arab Emirates' Defense Ministry said on Monday that the nation's air force "responded to a UAV detected over the country's territorial waters, approaching from Iran."
The ministry also issued a statement denying Iranian media reports that the Al Minhad Air Base, located to the south of Dubai, was targeted by missiles.
Iran's Foreign Ministry confirmed on Monday that Tehran's forces targeted U.S. bases in Jordan in response to Sunday's American strikes on Islamic Revolutionary Guard Corps units on Larak Island in the Strait of Hormuz.
The bases targeted in Jordan, the ministry said in a statement published by the semi-official Mehr News Agency, had been used to launch and support attacks on Iran.
The ministry added that Iran's armed forces "will not hesitate to exercise the inherent right of self-defense."
-ABC News' Joe Simonetti
