Benghazi, Libya - Libya's prosecutor general has ordered the arrest of four more officials, bringing to 12 the number held as part of an inquiry into this month's flood that killed thousands.

Flooding caused by hurricane-strength Storm Daniel tore through eastern Libya on September 10, leaving at least 3,893 people dead and thousands more missing.

The seaside city of Derna was the worst hit in the flash flood, which witnesses likened to a tsunami. The water burst through two dams and washed entire neighborhoods into the Mediterranean.

The four additional suspects, including two members of the Derna municipal council, were arrested for suspected 'bad management of the administrative and financial missions which were incumbent upon them,' said a statement issued overnight Thursday into Friday by the prosecutor general's office in Tripoli, western Libya.

On Monday, the office ordered the arrest of eight officials, including Derna's mayor, who was sacked after the flood.

Libya Prosecutor General Al-Seddik al-Sour belongs to the internationally recognized government in the country's west. A rival administration in the flood-stricken east is backed by military strongman Khalifa Haftar.

The eastern government has said it plans to host an international donors conference in Benghazi on October 10 to focus on the reconstruction of flood-ravaged areas, but its failure to involve the Tripoli government has drawn mounting criticism from donors.

Libya has been wracked by division since a NATO-backed uprising toppled and killed longtime dictator Moammar Gadhafi in 2011.

'Separate' reconstruction plans

The United States called on Libyans to set aside their political differences and agree a framework to channel aid to eastern towns.

'We urge Libyan authorities now to form such unified structures - rather than launching separate efforts - that represent the Libyan people without delay,' U.S. special envoy Richard Norland said in a statement Friday.

'A proposal to hold a reconstruction conference in Benghazi on October 10 would be much more effective if it were conducted jointly and inclusively,' he said.

Norland echoed concerns expressed by the United Nations that mechanisms need to be put in place to ensure that foreign aid is spent accountably.

'Libyans need to be assured public funds are used transparently, accountably, and that assistance goes to those in need,' the U.S. envoy said.

On Thursday during talks with the European Commission, U.N. envoy Abdoulaye Bathily said he had called for funds to be monitored.

'I ... emphasized the need for a joint assessment of reconstruction needs of storm-affected areas to ensure the utmost accountability in the management of reconstruction resources,' he said.

On Friday, the eastern authorities said they would begin paying compensation to people affected by the disaster, which a U.N. agency has said uprooted more than 43,000 people.

People whose homes were destroyed would receive $20,500 in compensation, Faraj Kaeem, the eastern administration's deputy interior minister, said separately.

He said those with partially destroyed homes would get about half that amount and those who lost furniture or household appliances would be given one-fifth.

The eastern administration announced on Wednesday the creation of a fund for the reconstruction of Derna.

The authorities have yet to specify how the new fund will be financed, but the eastern-based parliament has allocated about $2 billion to reconstruction projects.