HAVANA >> Tomas Luis Balseiro got up at 5 a.m. today to make the 90-mile bus journey from his home in Matanzas to the U.S. Embassy in Havana.

He had applied weeks ago for a visa to visit his gravely ill mother in Florida, and hours later he was waiting desperately outside the gates of the seaside diplomatic mission for a chance to get inside — or simply to learn the status of his application.

“For me it would be a victory just to see her alive,” said Balseiro, a 60-year-old food salesman, his eyes moist.

Thousands of islanders have had their travel plans thrown into limbo by the U.S. State Department’s announcement Friday that it was indefinitely suspending visa processing in Cuba. The move was attributed to a roughly 60 percent reduction in embassy staffing after 21 diplomats were left with serious health problems by mysterious attacks that have yet to be fully explained.

The U.S. government also issued a travel warning for the island, potentially threatening the livelihoods of thousands of Cubans who run private restaurants and home B&Bs catering to tourists, a group that increasingly includes Americans following a nearly three-year-old, partial thawing of relations that have been icy since the Cold War.

On the first business day since the announcement, about 300 people milled about in what is known as the “park of laments,” a small plaza near the embassy where visa-seekers wait for appointments.

Associated Press journalists spoke to about a dozen people there, all of whom worried that families separated by the 90 miles of the Florida Straits stand to suffer the most.

“My mother cried on the phone when we talked Friday,” said Carlos Sierra, a 31-year-old restaurant worker whose hopes for a family reunification visa to join his parents in the United States are now on hold.

He had hoped to find a job there and send money back to his wife and 6-year-old son. “For now,” Sierra said, shaking his head, “the only thing I can do is wait.”

Cuba’s government has criticized the U.S. response as “hasty” and expressed regret it was implemented before investigations yield conclusive results about the attacks. President Raul Castro’s government has denied responsibility.

U.S. officials have not identified whatever device might be responsible. They have pointedly not accused Cuba’s government directly of culpability, while criticizing it for failing to protect foreign diplomats on its soil.

The AP reported Monday that the attacks hit first — and hardest — among the United States’ spy network in the country.

Beginning in the morning, the “park of laments” filled up with people visibly on edge and chatting with each other to see if anyone had any information. Some paced about with their heads down, while others sat on narrow benches in the shade.

Three embassy staffers emerged to ask everyone to be patient before a fourth came out to line up those who had been summoned by phone. They were the lucky ones: Their visas had been approved prior to the announcement, and they would be allowed to pick them up.

About 2 million people of Cuban origin live in the United States, and just about everyone on the island has some family connection to the country.

Balseiro’s parents moved there in 1993 during a severe economic crisis, settled in Florida and found jobs as factory workers before retiring. Balseiro stayed behind to raise his two children.

Now in her 80s, his widowed mother is alone following hip surgery and suffers from dementia. He has already traveled twice to the United States, and on Monday he carried a white folder with pictures of his mother and letters from hospitals where she has been treated.

Balseiro had actually succeeded in getting an emergency visa appointment for Sept. 19, but the embassy closed for days around that date when Hurricane Irma swamped Havana’s coast and damaged the building.

Balseiro came to find out whether his appointment had been rescheduled, and he hoped the embassy would take pity on his “exceptional case.”

But an embassy staffer, shouting to be heard over the din of questions and complaints from the crowd, told everyone who wasn’t lined up to collect a previously approved visa that they should check the embassy’s website for “any other information.”

Dejected, Balseiro headed back to Matanzas where he said he would be able to get on the internet.

“Having your mother so far away, and so grave, it’s really hard,” he said.