Iran has said it is "fully prepared" to respond to the US if they "make the slightest mistake".
Delivering a speech on Iran state media, Mohammad Bagher Ghalibaf, speaker of Iran's Parliament, said the ceasefire represented a military victory for Iran.
"When the enemy fails to achieve its objectives, it means it has been defeated," he said.
Having now prevailed in war, he said, Iran would approach diplomacy with caution.
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Mr Ghalibaf, who also served as lead negotiator in peace talks, said: "We are fully prepared, if they make the slightest mistake, we will respond with full force."
He also doubled down on control over the Strait of Hormuz, and warned that actions Iran deemed as violating the ceasefire, including mine-clearing operations, would result in the crucial waterway being closed again.
The US and Iran remain far from any permanent peace agreement, Mr Ghalibaf said.
He said Tehran had "stated our demands firmly" but there were "misunderstandings" between the two sides.
Mojtaba Khamenei has said his navy 'stands ready' to fight
| GETTY"But in direct negotiations, we understood each other better," he added.
And a separate senior Iranian official said he would handing what Donald Trump has called "nuclear dust" to the US.
Iran's Deputy Foreign Minister Saeed Khatibzadeh said: "I can tell you that no enriched material is going to be shipped to United States.
"This is a non-starter and I can assure you that while we are ready to address any concerns that we do have, we're not going to accept things that are nonstarters."
LATEST ON IRAN WAR:
Donald Trump has warned he is ready to 'start dropping bombs again'
|GETTY
Both Iranian officials have made it clear an agreement with the US is far apart from coming together, with the 10 day ceasefire set to expire on Wednesday.
Mr Trump has threatened to "start dropping bombs again" unless the two sides can reach a long-term deal.
"We are still not there yet to move on to an actual meeting because there are issues that the Americans have not yet abandoned their maximalist position," Mr Khatibzadeh said.
Iran's supreme leader Mojtaba Khamenei said on Saturday Iran's "brave navy stands ready to make the enemies taste the bitterness of new defeats".
Iran foreign minister Saeed Khatibzadeh said 'no enriched material' would be sent to the US
|GETTY
Donald Trump did not address the Iran war on Saturday as he held a press conference on medicinal psychedelics in the Oval Office.
But after on Truth Social, he said: "Whether people like Israel or not, they have proven to be a GREAT Ally of the United States of America.
"They are courageous, bold, loyal, and smart and, unlike others that have shown their true colors in a moment of conflict and stress, Israel fights hard, and knows how to WIN!"
He also posted a four minute video of Frank Sinatra singing "My Way", which starts with the phrase "and now the end is near".