Israel's national electricity company on Monday cut off power for one hour to large parts of Nablus and Jenin, the two biggest Palestinian cities in the northern West Bank, saying the blackout was a warning over unpaid bills.

The company said it was owed large sums of money by Northern Electric, a Palestinian firm which buys electricity from Israel and distributes it to towns and villages in the northern West Bank.

The head of the board of directors of Northern Electric and the mayor of Nablus, Ghassan Shaka, said 18 municipal councils in the Nablus and Jenin area were cut off for about one hour, as an initial warning, causing disruptions in factories and companies.

Dozens of people were also stranded in elevators.

Shaka called on Palestinian citizens to pay their debts to Northern Electric, so that it would be able to pay its debt to the Israeli electricity company.

The Israeli electrical company said in a statement the Palestinian Authority and Palestinian companies owed it 1.9 billion shekels ($487 million) and that it had sent many notices warning of the pending step.

"The Israel Electric Corp. is committed to operate under the law to reduce the debt," the electric company said in a statement. "The Electric Corp. is compelled to act so as not to increase the debt beyond 2 billion shekels."

Electric company officials said the move was meant to pressure the Palestinian Authority to either collect the debt or at least reduce it. They said the company has also petitioned the High Court of Justice to require the state to reach an agreement to resolve the debt. The hearing is scheduled for April.

Palestinian officials have warned that if the Israeli government does not transfer frozen tax revenues collected on behalf of the Palestinians, the Palestinian Authority would break off security coordination with Israel.

Israel collects customs on goods that enter the Palestinian territories via its ports and airport. It has frozen the transfer of that money as "punishment" for "unilateral moves" by the Palestinians, including requests to join international organizations.