.RIGA, Latvia (AP) – Latvia’s coast guard on Monday removed more than 650 people from a stranded cruise ship after tugboats failed to pull the luxury liner off an underwater sand bank in the Baltic Sea.

In a five-hour operation, 651 passengers – most of them elderly Germans – and 11 crew members were transferred from the 660-foot-long Mona Lisa onto two naval ships, coast guard officials said.

They were taken about 22 miles to Ventspils, a port city in northwestern Latvia, and from there will go to the capital, Riga.

The passengers and crew members left the ship without incident, descending ladders to the naval ships, coast guard spokeswoman Liene Ulbina said.

She said 322 crew remained on board at the captain’s orders as the salvage operation continues.

It had been on its way from Kiel, Germany, to Riga with 984 people on board when it ran aground, officials said.

The Mona Lisa’s captain, a Greek national, agreed to evacuate the ship Monday after unsuccessful efforts to free it from the sand bank.

Initially, rescuers pumped ballast water from the ship to lighten the load, and then on Monday they tried pumping out fuel. But they were unable to free the liner.

Coast guard officials said the ship, which went into service in 1966, was not damaged and passengers were never at risk. The cause of the accident has not been determined.