A tentative truce has faltered as Israel vowed to retaliate after saying Iran launched missiles into its airspace more than two hours after the ceasefire was supposed to take effect.

Iran's military denied firing on Israel, state media reported — but explosions boomed and sirens sounded across northern Israel midmorning on Tuesday (evening AEST). Earlier, both Israel and Iran had accepted the ceasefire plan to end their 12-day war.

Israeli Defence Minister Israel Katz called the missiles a violation of the ceasefire and instructed Israel's military to resume"the intense operations to attack Tehran and to destroy targets of the regime and terror infrastructure".

The shaky agreement was first announced early on Tuesday morning by US President Donald Trump afterTehran launched a limited retaliatory missile attack on a US military base in Qatar on Monday.

Between Trump's post and the start of the ceasefire, Israel launched a blitz of airstrikes targeting sites across Iran before dawn and Iran replied with an onslaught of missiles that killed at least four people in Israel.

Israel said it had intercepted the midmorning barrage of missiles that came hours into the truce.

"Tehran will tremble," Israeli Finance Minister Betzalel Smotrich wrote on X after the missiles were launched.

Netanyahu agrees to ceasefire

Hours earlier, Israeli Prime Minister Benjamin Netanyahu announced he had agreed to the ceasefire deal with Iran.

"Israel has removed a dual immediate existential threat – both in the nuclear and ballistic missile fields," a statement from the prime minister's office said.

The statement said the Israeli military"achieved full air control over Tehran's skies, inflicted severe damage on the military leadership, and destroyed dozens of central Iranian government targets".

"In light of the achievement of the operation's objectives, and in full coordination with President Trump, Israel has agreed to the president's proposal for a bilateral ceasefire," the statement continued.

"Israel will respond forcefully to any violation of the ceasefire.

Ceasefire deal 'imposed on the enemy', Tehran claims

Iranian state media announced a ceasefire has been"imposed on the enemy" after the country's military response to "US aggression", hours after Iran's retaliatory attacks against a US base in Qatar.

"The Sepah (Islamic Revolutionary Guard Corps) successful missile operations in response to US aggression and the exemplary steadfastness and unity of our dear people in defending our land, has imposed ceasefire on the enemy," an anchor with state-run Iran National News Network said in a live broadcast.

The anchor did not give a time for when the ceasefire would take place.

US President Donald Trump requested the ceasefire between Iran and Israel"in a begging-like manner" shortly after Iran's strikes toward the US's Al Udeid base in Qatar, the anchor said.

"Last evening, only an hour after the successful missile attack by the Sepah on America's Al Udeid Base in Qatar, in a begging-like manner of urging, Trump requested the initiation of a ceasefire in the imposed Zionist enemy war against our country," the anchor said.

Trump details ceasefire deal on social media

Trump doubled down on his declaration of peace between Israel and Iran in a series of posts on Truth Social.

"Israel & Iran came to me, almost simultaneously, and said, 'PEACE!' I knew the time was NOW," Trump wrote on Truth Social.

"The World, and the Middle East, are the real WINNERS! Both Nations will see tremendous LOVE, PEACE, AND PROSPERITY in their futures.

"They have so much to gain, and yet, so much to lose if they stray from the road of RIGHTEOUSNESS & TRUTH.

"The future for Israel & Iran is UNLIMITED, & filled with great PROMISE. GOD BLESS YOU BOTH!"

He later asked parties not to violate the deal.

"THE CEASEFIRE IS NOW IN EFFECT. PLEASE DO NOT VIOLATE IT!" Trump said, signing off the post with"Donald J. Trump, President of the United States!"

Trump also credited the B-2 pilots who dropped missiles on Iran's nuclear facilities for today's deal.

The US president said the"deal" made between Iran and Israel was brokered thanks to the US-led attack on the weekend.

"In a certain and very ironic way, that perfect 'hit,' late in the evening, brought everyone together, and the deal was made!!!" Trump wrote.

Trump earlier claimed Israel and Iran"came to me" about peace after announcing the ceasefire on social media.

Flights impacted after Qatar strike

Qatar's major international airport has reopened its airspace after dozens of flights heading to the Middle East were diverted or cancelled.

However, travel chaos for Australians trying to head to the region for a holiday or stopovers to Europe is ongoing.

A Qantas Perth to London service was diverted to Singapore and a Perth to Paris flight returned to Perth.

The diversions impacted return services.

"We continue to monitor airspace availability closely and will alter our schedule as required," a Qantas spokesperson said.

"We have a number of flight path options that we utilise for our flights to Europe and these are reviewed regularly based on factors including weather and security."

Israel skies close again

Israel's skies are now closed to planes until further notice, the Israel Airports Authority said.

Israel began allowing limited outbound flights yesterday after closing the airspace on June 13.

This will likely impact repatriation flights planned by the Australian government.

A military repatriation flight, which departed Queensland for the United Arab Emirates, left Dubai earlier today and was seen heading south-east.

At least nine killed in Israeli strikes in northern Iran

At least nine people were killed and dozens wounded in Israeli strikes on residential buildings in northwest Iran early Tuesday local time, Iranian state media reported citing a regional official.

The attack in Gilan province wounded 33 people and destroyed four residential units, the deputy governor of Gilan said, according to state-affiliated media Tasnim news agency.

Of those killed and wounded, 16 were women and children, the governor said.

Surrounding houses were also damaged in the explosion, the governor said.

Video geolocated by CNN to the city of Astaneh-ye Ashrafiyeh, in Gilan, shows a large crowd of people and a ball of flames.