Mustafa Abdel Jalil, chairman of the ruling Libyan National Transitional Council (NTC), speaks during a press statement about the danger of federalism in libya, in Tripoli, March 6, 2012. (Xinhua/Hamza Turkia)

Head of Libya's ruling National Transitional Council (NTC) Mustafa Abdul Jalil said Tuesday that some Arab countries were supporting and financing the "sedition" in eastern Libya, local TV reported.

Jalil made the remarks at a press conference in Tripoli after tribal and political leaders in eastern Libya declared Cyrenaica an autonomous region during a ceremony held in the city of Benghazi on Tuesday.

Cyrenaica, known as Barca in Arabic, stretches from the central coastal city of Sirte, the birthplace of Libya's former leader Muammar Gaddafi, to the Egyptian border.

At the ceremony attended by 3,000 delegates, the tribal and political leaders also appointed a council to manage the region's affairs, and Ahmed Zubair al-Senussi was elected as the council's chairman.

Jalil said slammed the council's establishment as "the beginning of a plot against Libya."

The tribal leaders plan to name Benghazi, the cradle of the protests leading to Gaddafi's fall, as the autonomous area's capital. Under their plan, the region will have its own legislatures, courts and police force, while the power of foreign policy making will be left to the central government in Tripoli.

The declaration of autonomy was made despite the NTC' strong rejection and promise to decentralize the government across the country.

Since the end of Gaddafi's 42-year rule, some regional leaders have been calling for a return to federalism, the way Libya was governed in the mid-20th century.

The NTC has earlier voiced support for a decentralized political system, but not federalism.

Political changes in Cyrenaica can immensely impact the NTC's rule as the eastern region has most of Libya's oil wealth and Benghazi is home to the country's biggest state oil company.

Meanwhile, hundreds of protesters have reportedly taken to the streets in Benghazi and Tripoli, showing their support for the NTC.