Libyan leader Mustapha Abdel Jalil on Wednesday said he would defend national unity "with force" if necessary, after tribal leaders and a political faction declared autonomy for the country’s eastern region.

"We are not prepared to divide Libya," Abdel Jalil said, as he called on leaders in the eastern Cyrenaica region to engage in dialogue and warned them against remnants of the regime of slain leader Muammar Gaddafi in their ranks.

"They should know there are infiltrators and remnants of Gaddafi's regime trying to exploit them now and we are ready to deter them, even with force," he said in televised remarks during a conference in Misrata.

Abdel Jalil's comments come after tribal leaders in Libya's eastern region declared on Tuesday their plans for autonomy from the central interim government, the National Transitional Council (NTC), based in Tripoli.

The demand, which calls for a loose federation, is an attempt to return to a system similar to what had been in place until the 1950s in Libya, before Gaddafi took power.

The decision was made unilaterally by a group of militia commanders, politicians and tribal leaders, who stated at a Benghazi press conference that a loose federal state – named “Barqa” – was to be created.

It will also have its own parliament, police force and judiciary, the group announced. Yet foreign policy, the national army and oil resources are to be left to the central Tripoli government.   

Ahmed Zubair Al-Senussi, a member of Libya's ruling NTC, was elected leader of the region, according to the summit's closing statement, later posted online.

More than 3,000 people attended the conference where the decision was announced, an AFP journalist at the scene said.

The proposed region of Barqa will consist of roughly half the country, from the centre of Libya eastwards to the Egyptian border and extending south to the borders of Chad and Sudan.

The plan poses a danger to the country's future, say critics, as the eastern region contains a significant amount of Libya's oil.  

Tribal and political leaders in eastern Libya say the move is supported by the 1951 constitution, which was adopted under the monarchy of Ibrahim Al-Senussi.

Al-Senussi is a relative of the late king and was the longest-serving political prisoner under the Gaddafi regime.

Abdel Jalil described the plan for eastern autonomy as the "beginning of a conspiracy against Libya and Libyans."

"Some Arab nations, unfortunately, have supported and encouraged this," Abdel Jalil stated without specifying which countries he was referring to.

"These nations are funding this kind of unacceptable strife," he said at the press conference, adding that, "What happened today [Tuesday] is the beginning of a conspiracy against Libya and Libyans."

Elections in Libya are set to take place in June to select members of a national constituent assembly mandated with forming a new government and drafting a new constitution.