WASHINGTON, May 24 (Reuters) - The United States on Tuesday imposed sanctions on a Hamas finance official and a network of financial facilitators and companies that have generated revenue for the Palestinian militant group, the Treasury Department said.

The sanctions target Hamas' Investment Office, which holds assets estimated to be worth more than $500 million, including companies operating in Sudan, Turkey, Saudi Arabia, Algeria and the United Arab Emirates, the department said in a statement.

"Hamas has generated vast sums of revenue through its secret investment portfolio while destabilizing Gaza, which is facing harsh living and economic conditions," said Elizabeth Rosenberg, Assistant Secretary of the Treasury for Terrorist Financing and Financial Crimes.