Calls were mounting on Thursday for the ceasefire between the US and Iran to be extended to Israel's war with Hezbollah, after a massive wave of Israeli strikes on Lebanon killed more than 200 people.
US President Donald Trump has claimed victory in the Middle East war after agreeing a two-week truce to allow talks to end a conflict that has killed thousands and plunged the global economy into turmoil.
But the future of the negotiations was in limbo on Thursday after Iran denounced Israel's ongoing raids on Lebanon, and Tehran's ambassador to Pakistan deleted a social media post saying an Iranian delegation would arrive in Islamabad, which was set to host the talks.
An official at the Iranian embassy in Islamabad told AFP that Ambassador Reza Amiri Moghadam's post was removed "because of some issues" and declined to say whether the delegation was still expected.
At least 203 people were killed and 1,000 wounded in Israeli strikes on Wednesday, the Lebanese health ministry said.
There had been conflicting diplomatic signals about whether the fighting in Lebanon was included in the US-Iran truce -- but Washington said that it was not and Israel made it clear that it has no intention of holding off.
"We are continuing to strike Hezbollah with force, precision, and determination," Israel's Prime Minister Benjamin Netanyahu said, in a social media post.
"Our message is clear: anyone who acts against Israeli civilians, we will strike them. We will continue to hit Hezbollah wherever necessary."
- 'Running left and right' -
But, amid fears that the fragile truce could break down in the Gulf, there were international calls for the ceasefire to encompass Lebanon.
"Israeli actions are putting the US-Iran ceasefire under severe strain. The Iran truce should extend to Lebanon," the European Union's top diplomat Kaja Kallas said.
France's foreign minister Jean-Noel Barrot condemned the strikes as "unacceptable", while his British counterpart Yvette Cooper called for the ceasefire to include Lebanon.
The Lebanese prime minister's office said Thursday would be "a national day of mourning for the martyrs and wounded of the Israeli attacks that targeted hundreds of innocent, defenseless civilians".
Hezbollah said it had fired rockets towards Israel in response to what it called a violation of the truce.
US Vice President JD Vance backed Israel in saying Lebanon was excluded from the truce, days before he was due to lead talks with Tehran in Pakistan.
"If Iran wants to let this negotiation fall apart... over Lebanon, which has nothing to do with them, and which the United States never once said was part of the ceasefire, that's ultimately their choice," he said.
But Iran's speaker of parliament Mohammad Bagher Ghalibaf appeared to threaten the ceasefire, posting on X that the "workable basis on which to negotiate" had already been violated, making further talks "unreasonable".
Ghalibaf listed three alleged US violations of the truce plan: the continued attacks in Lebanon, a drone entering Iranian airspace and Washington's opposition to the country's right to uranium enrichment.
UN rights chief Volker Turk called the scale of killing in Lebanon "horrific", after strikes across the capital Beirut that came without warning triggered horror and panic.
"People started running left and right, and smoke was billowing," said Ali Younes, who was waiting for his wife near Corniche Al-Mazraa, one of the areas targeted.
- High-stakes talks -
The bellicose rhetoric came ahead of high-stakes talks in Pakistan expected on Friday or Saturday.
A key point of contention remains the Strait of Hormuz, through which a fifth of the world's oil as well as vast quantities of natural gas and fertilizer pass in peacetime.
Iran announced alternative routes on Thursday for ships travelling through the strait, citing the risk of sea mines.
But it was unclear if Tehran was in practice allowing vessels to pass through the strait, following reports on Wednesday suggesting it was shut -- something the White House called "completely unacceptable".
Pakistani Prime Minister Shehbaz Sharif, whose country mediated the ceasefire, called in a social media post for all parties to "exercise restraint and respect the ceasefire for two weeks" to allow diplomacy to take hold.
Further casting doubt on the truce's durability, Iranian state media announced fresh missile and drone attacks against US-allied Gulf states in retaliation for airstrikes on its oil facilities, with Kuwait, the UAE, Saudi Arabia and Bahrain all reporting strikes since the ceasefire took effect.
In Tehran, streets were quieter than usual on Wednesday, with many shops closed after a long and anxious night for residents fearing a massive US attack.
"Everyone is at ease now," said Sakineh Mohammadi, a 50-year-old housewife, adding she was proud of her country: "We are more relaxed."
