Iran said the United States violated a ceasefire after the U.S. conducted what it called defensive strikes in southern Iran, while U.S. Secretary of State Marco Rubio said negotiating a deal to halt the conflict could “take a few days.”

Iran’s Foreign Ministry said U.S. strikes in Iran’s southern Hormozgan province, where ‌Iranian media reported sounds of explosions early on Tuesday, represented a “gross violation” of the already tenuous ceasefire in place for nearly seven weeks.

Both sides had previously indicated there had been progress on a memorandum of understanding that could halt the war and restart shipping through the blockaded Strait of Hormuz, while giving negotiators 60 days to tackle more complex issues including Iran’s nuclear program.

Following strikes against targets ​that the U.S. said included boats attempting to lay mines and missile launch sites, Rubio told reporters on his plane ​in India’s Jaipur that the Strait of Hormuz had to be open “one way or the other.” Only a few dozen vessels have been passing through the strait compared ​with 125 to 140 daily before the war began on Feb. 28.

The standoff has caused a spike in oil prices and driven up the costs of fuel, fertilizer and food. Global benchmark Brent crude futures rose by about 3.5 per cent on Tuesday to around $100 US a barrel.

Iran’s Revolutionary Guard Corps ‌said on Tuesday it ​reserved the “legitimate ​and definite” right to retaliate ​against any ⁠ceasefire ⁠violations ‌by the U.S., adding that its ⁠air defence units had ‌shot down a U.S. MQ-9 drone ​and fired ⁠at a ⁠fighter ⁠jet ⁠that ​had entered Iranian airspace, ​state ⁠media reported. Meanwhile, a statement attributed to Iran’s Supreme Leader Mojtaba Khamenei said that countries in the region could no longer be a shield for U.S. bases.

Iran says nuclear issues to be negotiated later

Following a ceasefire in early April, the two sides have remained at odds on difficult issues including Iran’s nuclear ambitions, Israel’s war in Lebanon with the Iranian-backed Hezbollah militia and Tehran’s demands for the lifting of sanctions and the release of frozen assets.

Iranian sources said a framework deal is only about ending the war on all fronts, establishing a 30-day framework for movement through the Strait of Hormuz and possibly providing some financial relief.

Iranian Foreign Ministry spokesperson Esmaeil Baghaei said earlier that nuclear issues would only be negotiated after the framework accord was agreed.

U.S. President Donald 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.

The last deal over the nuclear program — struck in 2015 and torn up by Trump in 2018 — took years of negotiations between large teams of technical experts.

In terms of the framework to end the war, Iran would not charge tolls for ships to pass through the strait, 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.

In a lengthy post on Truth Social on Monday, Trump said any agreement to end the Iran war should include a requirement for several additional countries, including Saudi Arabia and Pakistan, to join the Abraham Accords, the U.S.-brokered agreements from Trump’s first term aimed at normalizing relations with Israel.

The president said he brought up the Abraham Accords plan with regional leaders on the weekend, but the proposal could add new diplomatic complications to the negotiations.

Saudi Arabia’s longstanding position has been that it would not sign the accords unless there is an agreement on a roadmap to Palestinian statehood.

WATCH | U.S. struggles to end war after initial shock and awe:

Why the U.S. ‘silver bullet’ strategy isn’t working against Iran | About That

More than 10 weeks into the war and without a clear end in sight, U.S. President Donald Trump says the ceasefire between the U.S. and Iran is on ‘massive life support.’ Andrew Chang explains why the U.S. strategy to end the conflict — which Trump initially said wouldn’t last more than a month — is falling short. (Photo credits: The Canadian Press, Reuters, Adobe Stock and Getty Images)

In another indication of the region’s tensions, Israeli Prime Minister Benjamin Netanyahu said in a statement on Tuesday that Israel was “deepening its operations in Lebanon,” saying the military “is operating with large forces in ⁠the field.”

Israel’s military said it was attacking Hezbollah infrastructure in Lebanon’s eastern Bekaa Valley and other areas. An Israeli airstrike on the village of Mashghara in the valley killed at least 12 people, Lebanese state media said.

As part of any initial deal, Iran has demanded a stop to the conflict in Lebanon.

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.