Iran said on Tuesday the United States had violated a ceasefire by striking targets near the contested Strait of Hormuz, potentially complicating efforts to bring the war to a close.

Further straining peace efforts, Israel pounded Lebanon with more than 120 air ‌strikes on Tuesday in one of the heaviest days of bombing in weeks, Lebanese security sources said. Iran has sought an end to Israeli attacks in Lebanon as part of any deal.

Iran’s foreign ministry said US strikes in Iran’s southern Hormozgan province, where Iranian media reported sounds of explosions early on Tuesday, represented a “gross violation” of a tenuous ceasefire in place for nearly seven weeks. The US said its attacks were defensive in nature, targeting missile sites and boats attempting to lay mines.

US Secretary of State Marco Rubio said it could take “a few days” to negotiate a deal to halt the conflict, after both sides had previously indicated progress on an initial agreement that would end hostilities and restart shipping through the Strait. That initial agreement would give negotiators 60 days to tackle more complex issues including Iran’s nuclear ⁠program.

Iranian media reported that the country’s negotiators had been pushing for the memorandum to include the release of billions of dollars of frozen assets.

Oil rises again

Following the US strikes, Rubio told reporters on his plane in India that the Strait of Hormuz had to be open “one way or the other.”

The war, which began with US and Israeli strikes on Iran on February 28, has caused an unprecedented oil supply shock, pushing up the costs of fuel, fertiliser, and food.

Traffic through the Strait of Hormuz, which normally carries about a fifth of global trade in oil and liquefied natural gas, has been a fraction of its usual level since the war began.

Global benchmark Brent crude futures rose by about 3.5% on Tuesday to around $100 a barrel.

‘Clock cannot be turned back,’ supreme leader says

The Revolutionary Guards said on Tuesday they reserved the right to retaliate to the strikes. They said air defense units had downed a US drone and fired at another drone and a fighter jet which they said had entered Iranian airspace over the Gulf region.

In comments posted on his Telegram channel on the occasion of the annual hajj pilgrimage, Iran’s Supreme Leader Ayatollah Mojtaba Khamenei said: “From now on, the slogans ‘Death to America’ and ‘Death to Israel’ will be the slogans of the Islamic nation and the oppressed people of the world.”

US President Donald ‌Trump has previously ⁠cited the slogans while justifying military action against Iran.

Frozen Iranian funds

Iranian and US officials have indicated that recent indirect talks made progress on a memorandum of understanding, or initial deal, that would lead to further negotiations over a final agreement.

Iran’s top negotiator, Mohammad Baqer Qalibaf, returned to Iran from Qatar after seeking the release of around $24 billion of frozen Iranian funds as part of the initial agreement, Iranian media reported.

Iran’s Fars news agency cited a source saying the funds were the last sticking point in the deal. Iran’s ISNA news agency said the negotiations in Qatar were “overall positive.”

While Iran’s core preconditions center on lifting the US naval blockade, nuclear issues, and sovereignty guarantees, Iran also wants a stop to the conflict in Lebanon, ⁠where a mid-April ceasefire has failed to halt fighting between Israel and Iran-backed militant group Hezbollah.

Israeli Prime Minister Benjamin Netanyahu said in a statement on Tuesday that Israel was “deepening its operations in Lebanon” and operating with “large forces in the field.”

Lebanese security sources told Reuters that Israeli strikes had hit across southern and eastern Lebanon on Tuesday. Lebanon’s health ministry said Israeli strikes in recent hours had killed 31 people and wounded 40, state news agency NNA reported early on Wednesday.

Initial deal would ⁠establish 30-day framework

According to Iranian sources, an initial deal would end hostilities on all fronts, get traffic moving through the strait over 30 days, and possibly provide some financial relief. More difficult issues such as Iran’s nuclear program would be negotiated in a second phase.

Iran has been letting some ships through the strait, giving preference to vessels linked to countries with which it has close ties, Reuters has reported.

Trump has said his key aim in ⁠the war is to prevent Iran from developing a nuclear weapon with its highly enriched uranium. Tehran denies any such plans.

Trump has also used the crisis to call on more Arab and Muslim states including Saudi Arabia to sign up to the Abraham Accords, which aim to normalise ties with Israel.

Saudi Arabia has said it would not sign the accords without a roadmap to Palestinian statehood.

Thousands have been killed in the wider conflict, mostly in Lebanon and Iran.