The United States has carried out strikes against 7000 targets inside Iran and hit more than 40 Iranian mine-laying vessels and 11 submarines, according to the Pentagon.
"Our objectives, given directly from our America-first president, remain exactly what they were on day one," Hegseth told reporters.
"These are not the media's objectives, not Iran's objectives, not new objectives. Our objectives - unchanged, on target and on plan," Hegseth added.
Hegseth told reporters that the objectives remained to destroy Iran's missile launchers as well as its defence industrial base and navy and to never allow Iran to get a nuclear weapon.
In the same briefing, General Dan Caine, the chairman of the Joint Chiefs of Staff, said the US military remained on track to achieve the objectives and the US was striking deeper into Iranian territory every day.
Director of National Intelligence Tulsi Gabbard said on Thursday during a hearing in front of the House intelligence committee that the US and Israeli objectives during the military campaign in Iran were not the same.
"The objectives that have been laid out by the president are different from the objectives that have been laid out by the Israeli government," Gabbard said.
"We can see through the operations that the Israeli government has been focused on disabling the Iranian leadership. The president has stated that his objectives are to destroy Iran's ballistic missiles launching capability, their ballistic missile production capability and their navy," she added.
European gas prices surged 25 per cent and oil gained 10 per cent on Thursday after Iran attacked energy infrastructure in the Middle East in retaliation against Israeli attacks on its gas facilities, marking the biggest escalation of the nearly three-week war.
The Iranian aerial attacks caused extensive damage to the world's largest gas plant in Qatar, targeted a refinery in Saudi Arabia, forced the United Arab Emirates to shut gas facilities and started fires at two Kuwaiti refineries.
The price of benchmark Brent crude rose to above $US119 a barrel on Thursday while gas prices in Europe were double the level seen in late February before the US and Israel launched their war on Iran.
"This latest escalation feels like a turning point for markets because the conflict is no longer just about military headlines or Strait of Hormuz closure," Charu Chanana, chief investment strategist at Saxo in Singapore, said.
"It is now hitting the plumbing of the global energy system. What is unsettling markets now is the growing stagflation risk," she added.
The leaders of the United Kingdom, France, Germany, Italy, the Netherlands and Japan issued a joint statement on Thursday urging "an immediate comprehensive moratorium on attacks on civilian infrastructure, including oil and gas installations".
They said they would act to stabilise energy markets and join "appropriate efforts" to open the Strait of Hormuz - the Gulf's oil chokepoint.
"We will take other steps to stabilise energy markets, including working with certain producing nations to increase output."
Major economies have been scrambling to cushion the effects of soaring oil prices after state oil giant QatarEnergy reported "extensive damage" from Iranian missile strikes on the Ras Laffan Industrial City in response to Israel's bombing of Iran's major gas field.
Ras Laffan processes about a fifth of the world's liquefied natural gas.
Saudi Arabia's main port on the Red Sea, where it has been able to divert some exports to avoid Iran's closure of the Gulf's Strait of Hormuz, was also attacked.
US Treasury Secretary Scott Bessent signalled a possible easing of sanctions on Iranian oil already at sea on Thursday.
"In the coming days, we may unsanction the Iranian oil that's on the water," Bessent told Fox Business.
"It's about 140 million barrels."
"In essence, we will be using the Iranian barrels against the Iranians to keep the price down for the next 10 or 14 days as we continue this campaign," he said.
with DPA
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