ATHENS – Frantic to lure tourists to prop up an economy brought down by COVID-19, Greece took the risky step of allowing cruise ships to dock as of Aug. 1 although the vessels have proved virtual petri dishes for spreading the virus, and with signs that travelers weren't willing to come on board.

Six of the country's main ports reopened to the ships but none were expected to dock for at least three weeks, near the end of a shortened summer season that has seen disappointing numbers for tourism despite the country's relatively safe record.

In a letter to the Cruise Lines International Association and three major cruise operators, Tourism Minister Harry Theoharis said the ports of Piraeus in Athens, Rhodes, Iraklio, Volos, Corfu and Katakolo would accept passengers, the state-run Athens-Macedonia News Agency (ANA-MPA) said.

After docking at one of the six ports, cruise ships will be able to travel elsewhere in Greece, depending on local coronavirus conditions although Shipping Minister Giannis Plakiotakis said cruises won't restart until Aug. 20 with no explanation why the ports would open now.

He said foreign cruise lines had expressed their interest in operating in Greek waters but that "cruises are an international operation and face serious problems because of the coronavirus,” heightened after 36 crew members on a Norweign ship were stricken.

On July 27, the European Maritime Safety Agency issued guidelines for the resumption of cruise ships in the European Union and countries in the European Economic Area. It states that "cruise operators need to ensure that cruises do not pose unacceptable health risks to passengers, staff and the general public, in particular when compared to other types of package holiday."

It recommends enhanced cleaning, keeping physical distancing of at least 1.5 meters, and the use of face masks if physical distancing cannot be maintained, CNN said.

Tourism is Greece's biggest revenue engine and brings in as much as 18-20 percent of the Gross Domestic Product (GDP) of 170.3 billion euros ($200.3 billion.)

Greece began to reopen its land borders in July to select countries, before allowing mostly European flights to all its airports on July 1 and expanding to other countries but still barring Americans, the United States hard-hit after President Donald Trump refused to order a lockdown.

In Greece, there have been over 340 confirmed infections among nearly 1.3 million incoming travelers, the civil protection agency said although the arrivals are far below expectations, showing people still largely afraid to travel internationally.

There's only about a 20 percent occupancy rate at hotels, said the Hellenic Chamber of Hotels, and local cruise operators do not expect bookings before September, too late to bring in any significant revenues, especially if Greece gets a second wave that could bring the economy to a near halt.