Describing the strikes against targets including boats attempting to lay mines and missile launch sites, Rubio said the Strait of Hormuz has to be open "one way or the other".
"The straits have to be open, they're going to be open one way or the other, so they need to be open," Rubio told reporters on his plane in India's Jaipur.
Despite a ceasefire in place since early April, US Central Command said in a statement on Monday it had carried out fresh strikes designed "to protect our troops from threats posed by Iranian forces".
Iran said on Monday it had downed a "hostile" stealth drone using a new air defence system, Iranian news agencies reported, without saying where it had come from.
The US attacks came as Iran's top negotiator and its foreign minister were in Doha for talks with Qatar's prime minister on a potential deal with the US to end the three-month-old war, an official briefed on the visit said.
Rubio told reporters in New Delhi earlier that the US would give diplomacy every chance to succeed before considering whether to deal with Iran in "another way".
There was a "pretty solid thing on the table", referring to talks over reopening the strait and a "very real, significant, time-limited negotiation on the nuclear matter", he said.
In a lengthy post on Truth Social on Monday, US President Donald Trump said talks with Iran were going "nicely", but warned of fresh attacks if they failed.
It "will only be a Great Deal for all, or no Deal at all," he wrote.
In another indication of the region's tensions, Israeli Prime Minister Benjamin Netanyahu said on Monday Israel would intensify strikes against the Iran-backed Hezbollah militia in Lebanon.
Israel's military soon thereafter said it was attacking Hezbollah infrastructure in Lebanon's eastern Bekaa Valley and other areas.
Israel and Lebanon agreed to a ceasefire in mid-April, but Israel has continued airstrikes it says are acts of self-defence against Hezbollah, which was not party to the truce.
The official briefed on the Iranians' Doha visit told Reuters the discussions focused on the Strait of Hormuz and Iran's stockpile of highly enriched uranium, while Iran's central bank governor attended to discuss the potential release of frozen Iranian funds as part of a final deal.
Iranian foreign ministry spokesperson Esmaeil Baghaei said earlier that nuclear issues would only be negotiated after the framework accord was agreed.
Trump has said his key aim in the war is to prevent Iran from developing a nuclear weapon with its highly enriched uranium. Tehran has consistently denied it has plans to do that.
Baghaei said the potential Iran deal contained no specific details on management of the Strait of Hormuz, through which about a fifth of the world's oil and liquefied natural gas usually flows.
Iran would not charge tolls for ships to pass through but there would be a cost for services offered such as navigation and steps to protect the environment, he said, under a protocol to be agreed with Oman, which lies on the opposite shore of the waterway.
Citing a Middle East diplomatic source, Japan's Nikkei newspaper reported the US and Iran were discussing a plan to open the strait about 30 days after reaching a deal to end hostilities.
Since the US and Israel launched strikes on Iran on February 28, only a few dozen vessels have been passing through the Strait of Hormuz compared with 125 to 140 daily previously.
The stand-off has caused a spike in oil prices and driven up the costs of fuel, fertiliser and food. In early Asian trade on Tuesday, US West Texas Intermediate crude was up slightly from Monday's last traded price but down 5.5 per cent from Friday's close.
with AP
