Rubio told reporters on Friday after meeting G7 counterparts in France that Washington was "on or ahead of schedule in that operation, and expect to conclude it at the appropriate time here - a matter of weeks, not months".
While he said the US could achieve its aims without ground troops, he acknowledged it was deploying some to the region "to give the president maximum optionality and maximum opportunity to adjust the contingencies, should they emerge".
Rubio discussed with G7 foreign ministers the possibility that Iran, even after the conflict ends, could try to impose shipping tolls through the Strait of Hormuz. He said European and Asian countries that benefit from trade through the waterway should contribute to efforts to secure free passage, downplaying US dependence on the trade.
Washington has dispatched two contingents of thousands of Marines to the region, the first of which is due to arrive around the end of March aboard a huge amphibious assault ship. The Pentagon is also expected to deploy thousands of elite airborne soldiers.
The deployments have raised concerns that the war, which the US and Israel launched on February 28 with airstrikes that killed Iran's supreme leader and other top officials, could turn into a prolonged ground battle.
Iran's response, striking US and Israeli targets in the region as well as civilian targets in Gulf Arab nations and shipping, has disrupted global trade in energy and other commodities, raising fears of rising prices and recession.
President Donald Trump has appeared anxious to wind down the unpopular war, and emphasised this week what he has described as productive negotiations aimed at a diplomatic solution, despite repeated assertions from Tehran that no such talks have begun. On Thursday, he extended a deadline by 10 days for Iran to reopen the blockaded Strait of Hormuz or face attacks against its civilian energy grid.
Trump's special envoy Steve Witkoff said the US was hopeful of meetings with Iran within a week and he expects an Iranian response soon to Trump's 15-point proposal to end the war.
Witkoff said there were clear red lines for the US, including no uranium enrichment by Iran and the country giving up what he said was 10,000kg of enriched stockpiled material.At least five people were killed and seven were injured after a US-Israeli attack on a residential unit in Iran's northwestern city of Zanjan, Iranian media reported on Saturday.
Iranian Foreign Minister Abbas Araqchi said on X that Israel, in co-ordination with the US, had also hit two steel factories and a power plant.
"Attack contradicts POTUS extended deadline for diplomacy. Iran will exact HEAVY price for Israeli crimes," Araqchi said, using an acronym for the US president.
In Iran, more than 1900 people have been killed and at least 20,000 injured. Attacks on Israel by Iran's Lebanese ally Hezbollah have also prompted an Israeli onslaught that has displaced a fifth of Lebanon's population.
The Israeli military on Friday said Iran had launched missiles towards Israel. A 60-year-old man was killed in the Tel Aviv area, the ambulance service said.
Twelve US military personnel were wounded - including two seriously - by an Iranian missile and drone attack at the Prince Sultan airbase in Saudi Arabia, a US official told Reuters on Friday. The Wall Street Journal reported that several refuelling aircraft were damaged in the attack.
