Iran's foreign ministry said Monday that the United States was not serious about pursuing diplomacy, citing what it called "violations" of their two-week ceasefire.
"While claiming diplomacy and readiness for negotiations, the US is carrying out behaviors that do not in any way indicate seriousness in pursuing a diplomatic process," said ministry spokesman Esmaeil Baqaei in a weekly press briefing.
He said a US attack on an Iranian cargo ship early Monday, the US naval blockade on Iranian ports, and delays in implementing a ceasefire in Lebanon were all "clear violations of the ceasefire".
Iran has been at war with Israel and the United States since February 28 when strikes killed supreme leader Ali Khamenei, triggering a conflict that has engulfed the region.
Tehran and Washington have since held a round of negotiations which failed to culminate in a deal to end the war. It took place against the backdrop of a fragile two-week ceasefire which began on April 8.
US President Donald Trump said Sunday he had ordered US negotiators to travel to Pakistan on Monday to hold another round of talks, but Iran has yet to confirm its attendance.
"As of now, while I am at your service, we have no plans for the next round of negotiation, and no decision has been made in this regard," said Baqaei.
Key sticking points include Iran's stockpile of highly enriched uranium and the status of the strategic Strait of Hormuz, which has been largely closed since the outbreak of the war.
"Regarding the issue of transferring enriched uranium, neither during this period of negotiations nor before has transferring it to the United States been discussed," Baqaei said.
"It was never raised as an option for us," he added.
