Rights groups and observers in the country have also criticised memorandums of understanding reached between the two governments aiming to crack down Mediterranean migration flows.

The energy deal was signed between Libya's National Oil Corporation (NOC) and Italian energy firm Eni during a visit by Italian Prime Minister Giorgia Meloni and an accompanying delegation to Tripoli on Saturday, while the memorandums were signed between the two countries' foreign ministers.

The GNU's outspoken oil and gas minister Mohammed Aoun spoke to Al-Wasat's WTV shortly after the gas deal was signed, calling it "illegal" and saying it "lacks equality between the Libyan and Italian sides".

He said his ministry was "bypassed" on the deal which he reiterated was illegal and pledged to "rectify".

On Sunday, the ministry released an official statement reiterating Mr Aoun's points, further criticising the deal for increasing the Italian side's shares from 30% to 37%.

During a press conference after the signing of the deal on Saturday, a reporter from the pro-GNU Lana news agency asked the NOC chairman Farhat Bengdara why Mr Aoun had been absent from the ceremony.

In a strongly worded response, Mr Bengdara said his company "works according to the law, and whoever sees this procedure as illegal must go before the court".

He added that GNU ministers had been involved in approving the NOC negotiation team and that the government had international recognition.

He also said the agreement was a "message to international oil companies" to return to Libya to continue with energy exploration as well as a "clear indication that the oil sector in Libya is free of risks".