The European Union is imposing sanctions on three Libyan officials accused of hindering the country's new UN-brokered unity government as it begins its work.

The EU identified the three in its official journal as Agilah Saleh, parliament head in the eastern city of Tobruk; Khalifa Ghweil, head of the so-called National Salvation Government; and Nuri Abu Sahmain, who leads the outdated General National Congress.

The three face travel bans and having their assets frozen.

Libya has been split between rival governments since 2014, a consequence of the chaos that engulfed the country after a 2011 uprising that toppled and killed dictator Muammar Gaddafi.

UN-brokered talks to establish a unity government have faced numerous obstacles.

The EU said the men have been "obstructing the implementation" of last December's Libyan political agreement and the formation of the so-called Government of National Accord.

It added that the EU "remains concerned about the situation in Libya, and in particular about acts that threaten the peace, security or stability of the country, and that impede or undermine the successful completion of Libya's political transition".

Amid a power struggle and the security vacuum, Islamic State (IS) has gained a foothold in Libya. It has taken over the central city of Sirte and carried out deadly attacks across the country.

The hope of the international community is that an operational unity government could eventually seek military help against the extremists.

The EU also wants a stable government to help stop the flow of migrants into Europe.