In a social media post, Trump said the US was close to meeting its goals but insisted that other countries should take the lead in policing the vital shipping lane of the Strait of Hormuz, whose near-closure threatens a global energy shock.
Trump and his administration have sent mixed messages about US goals throughout the war, now entering its fourth week, leaving traditional US allies struggling to respond.
Trump has suggested the war could wind down as the Iranian threat was being eliminated, while at the same time US Marines and heavy landing craft head to the region on a mission whose goals are not immediately clear.
"We are getting very close to meeting our objectives as we consider winding down our great Military efforts in the Middle East with respect to the Terrorist Regime of Iran," Trump said on Truth Social.
"The Hormuz Strait will have to be guarded and policed, as necessary, by other Nations who use it — The United States does not!" he added.
"If asked, we will help these Countries in their Hormuz efforts, but it shouldn't be necessary once Iran's threat is eradicated."
More than 2000 people have been killed in Iran since the US and Israel attacked on February 28, while American voters appear increasingly concerned at signs the war could expand further. Vital energy infrastructure in Iran and neighbouring Gulf states has been attacked, sending oil prices up 50 per cent.
Energy price shocks are also fuelling inflation, hitting consumers and businesses hard - a major political liability for Trump as he seeks to justify the war to the US public before November elections in which he could lose control of Congress.
Trump had also accused NATO allies, which have not been consulted about the war, of cowardice over their reluctance to help open the strait.
Iranian gas supplies to Iraq reportedly resumed after flows were halted by an Israeli attack on Iran's main gas field, South Pars, on Wednesday.
As the fighting continued, Iranian media said US-Israeli forces had attacked the Shahid Ahmadi-Roshan Natanz enrichment complex on Saturday morning. Technical experts found that no radioactive leaks had occurred and nearby residents were not at risk. Israel said it was unaware of such a strike while the head of the International Atomic Energy Agency (IAEA) said it was investigating.
Russia called it "a blatant violation of international law".
Israel also attacked Beirut, saying it was targeting the Iran-backed Lebanese Hezbollah militia, in the deadliest spillover from the war on Iran since Hezbollah fired on Israel in support of Tehran on March 2.
Defence Minister Israel Katz said Israel was "determined to continue leading the attack against the Iranian terrorist regime, to behead its commanders and to thwart its strategic capabilities until any security threats to Israel and US interests in the region are removed".
Air raid sirens in Israel warned of incoming missiles from early morning, sending millions to shelters as the blasts of interceptions rang out from above. There were no immediate reports of casualties. Iran fired two ballistic missiles towards the US-British military airport on the island of Diego Garcia, 3800 km away in the Indian Ocean but did not hit the base, the Wall Street Journal reported.
Natural gas prices in Europe surged as much as 35 per cent this week as Iran and Israel hit some of the region's most important gas infrastructure.
The Strait of Hormuz, conduit for around a fifth of global oil and liquefied natural gas supplies, has been effectively closed to most shipping. Leading allies of the US from Europe as well as Japan and Canada have pledged to join "appropriate efforts" to ensure safe passage through the strait, but Germany and France have spelled out that fighting must stop first.
