(CNN) -- The wife of imprisoned U.S. State Department contractor Alan Gross traveled to Cuba Tuesday as part of her ongoing effort to free her husband.
Judy Gross did not talk to a CNN reporter outside Havana's Jose Marti International Airport, and she and Gross' attorney quickly boarded a bus provided by the Cuban government.
Last week, Gross' mother died after a long fight with cancer, Gross' attorney, Scott Gilbert, said.
The Cuban government refused Gross' request to travel to the United States to say goodbye to Evelyn Gross before she died. Gross had promised that after seeing his mother he would return to his prison cell at a military hospital in Havana.
"We would like to convey our heartfelt condolences to his relatives," Cuban Ministry of Foreign Affairs official Josefina Vidal said in a statement. "It is necessary to clarify that neither the Cuban penitentiary system nor the U.S. penitentiary system provide the possibility for inmates to travel abroad, no matter the reason. "
Gross, 65, is serving a 15-year sentence for bringing satellite communications equipment to Cuba as part of his work as a subcontractor for the U.S. Agency for International Development. He was convicted in March 2011.
U.S. officials said Gross was merely trying to help Cubans bypass the island's stringent restrictions on Internet access and have said his imprisonment is one of the major obstacles to improved relations with Cuba.
In April, Gross embarked on a hunger strike to protest his continued imprisonment. He later said he was suspending his hunger strike after his mother pleaded with him to begin eating again.
Since his arrest, Gross has suffered a slew of health problems, his attorney said, and lost more than 100 pounds.
"Alan is confined to one room, 23 hours a day." Gilbert said during an interview with CNN in April. "He spends his day there in pajamas, he's fed meals in his room. He's let out for an hour a day, to exercise an hour a day in a small, walled courtyard where you can barely see the sky."
Cuban officials have said they want to negotiate Gross' case with representatives of the United States in conjunction with the fates of three Cuban intelligence operatives serving lengthy sentences in U.S. prisons.
But U.S. officials have called that effort blackmail and said the cases are separate matters because Gross was not working as a spy in Cuba.
The diplomatic impasse is taking its toll on Gross, Gilbert said.
"The White House has yet to engage on this issue; we need the president to make this a priority. Without that, Alan will die in Cuba," Gilbert said.