Police in Moscow are in a standoff with a man who took hostages at a bank during a robbery attempt.

Russian news agencies cited the Interior Ministry, which manages police departments, as saying Wednesday night that all hostages have been freed except for a cashier who took refuge in a secure room in the bank.

The state news agency Tass cited police as saying that the man was demanding a large sum of money and threatening to set off a bomb, although it wasn't clear if he possessed any explosives.

There were no immediate details about whether the others in the bank were released or were able to escape, or how many were held.

The reports said the man was masked and brandished what appeared to be a pistol.