Libyan security officials say an explosion went off next to the parliament in the capital, Tripoli, as lawmakers were in session.

The officials, who are loyal to the Islamist-backed government based in Tripoli, say no casualties were reported.

The officials say the parliament session continued undeterred, with lawmakers debating names for a potential national unity government. The officials spoke on condition of anonymity because they aren't authorized to speak to reporters.

No one immediately claimed responsibility for the explosion.

Libya is split between Tripoli's government and an internationally-recognized government in the country's east.

The U.N. is trying to broker a deal to unify the two governments. U.N. envoy for Libya, Bernardino Leon, said late Tuesday that the U.N. hopes to announce a proposal for a national unity government Wednesday.