Iranian Foreign Ministry Spokesman Esmaeil Baghaei said diplomatic efforts were continuing in parallel with the response by the country's armed forces.
Speaking at his weekly press conference on Monday, Baghaei was responding to a question from the state-run IRNA news agency about recent reports suggesting Qatar had put forward new initiatives to revive negotiations, including speculation over a proposed 10-day ceasefire between Tehran and Washington.
Baghaei said mediators were actively working to prevent further escalation.
"At the same time, the Islamic Republic of Iran will spare no effort to stop the American crimes," he stated, according to IRNA.
"I reiterate that the diplomatic apparatus, in coordination with the defenders of the homeland in the armed forces, continues to carry out its duties," Baghaei added.
"The proposals put forward through the mediators have been conveyed to us, and we have received them. However, I prefer not to go into their details at this stage," he noted.
Baghaei also said "insisting on the dichotomy of war or negotiations is not beneficial for our country," adding that the text of the memorandum of understanding with Washington was clear and that there was "no justification" for the United States to violate it.
Meanwhile, a source at Pakistan's Ministry of Interior told Al Jazeera that Iranian Interior Minister Eskandar Momeni was due to visit Islamabad on Monday evening amid the continuing military escalation between Washington and Tehran.
The source said the Iranian minister would deliver a message from Iranian President Masoud Pezeshkian on the current situation to Pakistan's leadership, as Islamabad continues to play a mediating role between the United States and Iran.
The developments came as the United States expanded its strikes on Iran on Monday, targeting provinces across the country, including one that hosts a nuclear power plant, while Tehran continued its attacks across the region.
The Middle East war resumed after a weeks-long lull following an agreement signed in June, while oil prices climbed to a one-month high as both sides battled for control of the strategic Strait of Hormuz.
After its truce with the United States collapsed, Tehran reimposed its blockade of the waterway, through which around one-fifth of global oil supplies had passed before the war, while Washington responded by again blockading Iranian ports.
While US strikes since the resumption of hostilities had largely focused on areas near the Strait of Hormuz, Monday's attacks targeted provinces in central and northern Iran, according to state media and local authorities. All of the provinces struck host military bases and air defence systems.
In Bushehr, home to Iran's only operational civilian nuclear power plant, Governor Mohammad Mozaffari told IRNA, "A few minutes ago, several locations in Bushehr city were hit by American enemy projectiles."
In East Azerbaijan province, local crisis management chief Majid Farshi told IRNA that "one person was martyred and several others injured" in an attack.
Iran also urged the International Atomic Energy Agency (IAEA) on Monday to condemn US strikes that it said targeted the under-construction Darkhovin nuclear power plant in the country's southwest.
"Iran... expects the IAEA Board of Governors and the Director General of the IAEA, who from time to time makes political statements regarding the Iranian nuclear issue, to clearly state their position on this matter in condemning the US crime," Baghaei said during the Tehran press conference attended by AFP.
US Central Command (CENTCOM) said on Sunday it had completed the ninth consecutive night of strikes against Iran, while US Secretary of State Marco Rubio said he would "continue to try" to reach a diplomatic solution.
The latest attack followed a weekend in which the United States announced three additional military fatalities and one service member missing in action.
Two US service members were killed in Iranian missile and drone attacks on Jordan on Friday, while another died in northern Iraq during the controlled detonation of unexploded ordnance from a downed Iranian drone, according to CENTCOM.
US President Donald Trump said on Sunday that the latest American strikes on Iran "hit them very hard" in honour of the fallen US personnel.
The latest deaths bring the confirmed number of US military personnel killed since the start of the conflict, which began with a large-scale US-Israeli strike on Iran, to 17.
On Friday, Iran's Ministry of Health said 50 people had been killed in the latest attack and more than 500 others wounded.
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