ISIS has released images claiming to show the execution of three 'spies' in the groups' Libyan stronghold by a man in a wheelchair.

The photographs allegedly sees the wheelchair-bound executioner crucifying one of the men in Sirte, central Libya, on Tuesday.

The images were released on the same days as U.S Secretary of State John Kerry pressed for direct action against ISIS in Libya during a meeting of Western leaders in Rome.

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Execution: One of the photos shows an ISIS fighter sat in a wheelchair next to a man kneeling in an orange jumpsuit while tied to a rope before the 'crucifixion' in Sirte, central Libya

One of the photos shows an ISIS fighter sat in a wheelchair next to a man kneeling in an orange jumpsuit while tied to a rope before the 'crucifixion'.

Another image shows a man with what appears to be a bloodied and battered face, tied up and 'crucified' on the structure. A note taped to his body reportedly reads 'spy'.

A third image shows a man without a note, however, it is not clear whether or not this is the same person or whether he is dead or alive.

The executions took place in Sirte, the birthplace of former Libyan dictator Muammar Gaddafi, and the group's only stronghold in the North African country.

ISIS forces have attacked oil infrastructure and established a foothold in Sirte, exploiting Libya's current power vacuum where two rival governments have been battling for supremacy.

Crucified: A man has been tied up and 'crucified' on the structure, with a note reading 'spy' taped to his body

Mystery: A third image shows a man without a note, however, it is not clear whether or not this is the same person or whether he is dead or alive

The images were released on Tuesday as the US and French governments pressed for direct action against ISIS in Libya.

U.S Secretary of State John Kerry warned that ISIS is threatening Libya and could seize the nation's oil wealth to fuel its war and expand in the country and elsewhere.

'That country has resources. The last thing in the world you want is a false caliphate with access to billions of dollars of oil revenue,' Kerry said.

The Secretary of State spoke during a meeting of the foreign ministers of 23 countries to review the fight against ISIS, held in Rome, Italy, on Tuesday.

Defence ministers from the anti-IS group are due to meet in Brussels next week to discuss further options, while Kerry said he expected further consultations with allies at a security conference in Munich, Germany later this month.

Time to fight: US Secretary of State John Kerry speaks during a press conference following a summit with the foreign ministers of 23 countries to review the fight against ISIS, held in Rome, Italy, on Tuesday

A Libyan fireman stands in front of smoke and flames rising from an oil storage tank in northern Libya's Ras Lanouf region last week, after it was set ablaze following attacks launched by ISIS

While ISIS remained undefeated, it had suffered many setbacks, Kerry said, losing 40 per cent of the territory it once controlled in Iraq and 20 percent of its lands in Iraq.

'Our advances .. are undeniable. We have launched nearly 10,000 air strikes, we have interrupted their finance mechanisms, they have had to cut the salaries of their fighters, we have interrupted their capacity to get revenues,' Kerry said.

The one-day Rome meeting took place as talks have begun in Geneva to try to end the five-year-old Syrian civil war, which has killed at least 250,000 people, driven more than 10 million from their homes and drawn in the United States and Russia on opposite sides.

While Washington has long said Syrian President Bashar al-Assad has lost the legitimacy to lead, it has made clear that its first priority is to try to rein in Islamic State group.

'If you want to beat Daesh quickly, then get a negotiated deal to end the Syria war,' Kerry said.