Four cruise ships headed toward the Texas port of Galveston carrying some 20,000 passengers cannot return home following the destruction wrought by Hurricane Harvey, now a tropical storm but still packing heavy rains.

According to ABC13, three of the ships are owned by Carnival Cruises and a remaining boat belongs to Royal Caribbean. The Carnival Freedom and Valor ships, diverted to New Orleans to stock up on food and supplies, offered passengers the choice of making their own way to Galveston or re-boarding the ship, which will return to the Texas port city when officials have deemed maritime traffic safe.

Carnival Corp said in a statement on its Facebook page, "Given the severity and projected path of the storm along with potential challenges guests may encounter attempting to travel back to Galveston independently, we are strongly encouraging them to remain on board as we intend to return the ships to Galveston as soon as feasible."

The Carnival Breeze ship still remains in Cozumel, Mexico, and will return to Galveston on Sunday, while the Royal Caribbean's Liberty of Seas cruise ship left Cozumel on Friday and is scheduled to reach Galveston on Sunday.

"We will continue to remain in close contact with port officials regarding their plans to re-open once the storm has passed," spokeswoman Christine de la Huerta for the Carnival Corporation said.

Peter Simons, the port's interim director, told the Houston Chronicle newspaper that officials are still ascertaining whether the ships can return on Sunday.

"We're working with the cruise lines, the Coast Guard and the pilots to see what can be done to bring the cruise ships in as quickly but as safely as possible," Simons said in a statement.

The slow-moving storm is projected to remain in the region for at least three more days, dumping heavy rains in the area and causing massive flooding.