The U.N. envoy to Libya says corruption and fight over resources among rival factions are core issues impeding progress in resolving the country's turmoil.

Ghassan Salame told the Qatar-based Al-Jazeera TV late on Wednesday that building national institutions in charge of a fair distribution of wealth is "the only solution for Libya."

He spoke ahead of the April 14-16 national conference that all Libyan factions are expected to attend.

Salame denounced prevalent corruption among Libya's political elite that ignores "citizens who are poor and miserable" in the oil-rich country.

He says it's "saddening to see them taking over the wealth, investing it overseas, and engaging in money laundering."

Libya slid into chaos after the 2011 uprising that toppled long-time ruler Moammar Gadhafi with rival administrations and militias fighting one another.