The US military has launched fresh strikes on southern Iran, targeting Iranian missile sites and boats allegedly attempting to lay mines.

US Central Command said the strikes were carried out in “self-defence” and were intended “to protect our troops from threats posed by Iranian forces” the BBC reports.

Central Command spokesman Captain Tim Hawkins said the US military “continues to defend our forces while using restraint during the ongoing ceasefire”.

The strikes came as the Iranian foreign ministry spokesman Esmail Baqai said some progress had been made in recent talks with Washington, although a deal to end the conflict was “not imminent”.

Hawkins added that the operation targeted an area near Bandar Abbas, the southern port city 1100km from Tehran that hosts an Iranian naval base on the Strait of Hormuz.

Iranian state media has also reported that local officials in Bandar Abbas were investigating a series of explosions heard in the area. Iran has yet to respond to the latest US strikes. It remains unclear what effect they may have on any potential agreement currently being discussed between Washington and Tehran.

US and Iranian forces have observed a ceasefire since early April while Iran has maintained controls on Gulf shipping through the Strait of Hormuz even as the US Navy has sought to blockade Iranian ports.

The strikes on Iran’s southern port city of Bandar Abbas may be linked to intelligence gathering around the Strait of Hormuz, Al Jazeera has since reported, citing a former US diplomat and Pentagon official.

Adam Clements told Al Jazeera he did not believe the strikes would cause the emerging peace deal to “fall apart” adding that “there is very limited information coming from the US side; we don’t know the extent of the operation,” and at present “it’s hard to say whether this skirmish is unusual.”

“We were told that Trump was going to launch an attack exactly a week ago today, but decided to delay that due to intervention from Gulf countries,” Clements was quoted as saying, and in downplaying the US strikes that “this incident will be seen as a small hurdle, but it won’t derail the peace talks at this stage.”

Addressing US Central Command claims that Iran was laying mines in the waterway, Clements said such an action would “solicit a lethal response”.

“It should not come as a surprise to the Iranians that the US would act this way,” he said.

Meanwhile, US crude prices fell sharply after reports that the Strait of Hormuz could reopen amid talks between Washington and Tehran with West Texas Intermediate crude dropping 6.1% in early Asian trading – falling $5.90 to $90.73 a barrel.