SAN JUAN, Puerto Rico – The disaster wrought by Hurricane Maria has set off a fierce exodus across Puerto Rico, where friends, family and co-workers are arguing fiercely over the morality of leaving the blacked-out island for the U.S. mainland versus fulfilling a patriotic duty to rebuild.

More than 340,000 Puerto Ricans have left since the storm hit Sept. 20 according to airport officials  and some experts estimate more than 600,000 more could leave in the next two years. That’s on top of a similar-size exodus over the last decade of economic crisis, creating a massive population loss for the U.S. territory of 3.4 million.

Most of those who have left went on their own. Aid groups and the U.S. government helped evacuate large numbers of the elderly and sick. The Federal Emergency Management Agency said it has offered to help relocate those still in temporary shelters, about 2,400 people as of Friday, to temporary housing on the mainland.

Many of those leaving are facing recriminations from fellow Puerto Ricans who accuse them of abandoning their homeland when it needs them the most.

Nilsa Montes, an unemployed waitress, said her friends and family often talk negatively about those who have left.

“They always get criticized because people point out, ‘Hey, you didn’t stay,’” she said. “I wouldn’t move because I don’t give up.”

The drive to stay in Puerto Rico and help rebuild has become a sociocultural movement with its own slogan echoing Montes: “Yo no me quito,” or “I’m not giving up.”

Those four words have become a popular hashtag posted next to pictures on social media of Puerto Ricans rebuilding homes, distributing food and water or simply relaxing on the beach. Some who left or are leaving respond with messages that they would stay if someone found them a job, power or water.

The “yo no me quito” message carries so much meaning that when Denise Centeno, who runs the Hispanic Family Counseling center in Orlando, Florida, recently played “The Blessed Island” by a singer who included those four words in its lyrics, she provoked an unexpected reaction from clients.

“People who had come from Puerto Rico were crying with a horrible feeling of guilt,” she recalled. “They feel like, ‘Wow, I gave up. I wanted to stay.’… Of course they feel hurt.”

In a recent chain of comments on Twitter about the merits of staying against going, one Puerto Rican wrote: “Those of you who left are fleeing from catastrophe while those of us who stay will lift the flag even higher than it already is.”

People who have left bridle at the criticism.

Carlos Rodriguez, an unemployed security guard and volunteer paramedic, moved with his wife and two young girls to the U.S. mainland on Nov. 2 from their hometown of Cayey, nestled in Puerto Rico’s once-lush central mountains. The family lost its home and car to the storm and is now sleeping on the couch of a relative in Providence, Rhode Island, while looking for permanent housing and a job for Rodriguez. His parents, however, stayed in Puerto Rico.