Havana, Cuba (CNN) -- Former New Mexico Gov. Bill Richardson, who arrived in Cuba this week to try to negotiate the release of jailed American contractor Alan Gross, said Friday he has not been allowed to meet with him.
Richardson said he won't leave Cuba until he has an opportunity to meet with Gross. He arrived in Havana Wednesday.
"I was informed by the Cuban government that one of my requests -- to see Alan Gross in his hospital -- would not be possible," Richardson told reporters Friday. "I feel that is something that I need to do. I promised his wife, Judy, that I would visit him. There are reports of Mr. Gross' health deteriorating."
Richardson had planned to leave Saturday afternoon, but said he will now stay until he sees Gross.
"My main message is that the key to improving relations between the U.S. and Cuba -- which has been one of my objectives -- is the release of American Alan Gross," he said.
An exclusive report Wednesday by CNN's Wolf Blitzer on "The Situation Room" said Richardson was invited by the Cuban government for the specific mission of trying to negotiate the release of Gross. Richardson is expected to spend "the next few days" in Havana, Blitzer reported.
"We are aware of Gov. Richardson's trip to Cuba and have been in contact with him," State Department spokeswoman Victoria Nuland told CNN. "While Gov. Richardson is traveling as a private citizen, we certainly support his efforts to obtain Alan Gross' release."
A statement issued Wednesday on behalf of the Gross family said, "We are pleased that the Cuban government invited Gov. Richardson to Havana."
"We welcome any and all dialogue that ultimately will result in Alan's release," the statement said. "We are grateful to Governor Richardson for his continued efforts."
Last month, Cuba's highest court upheld the 15-year sentence imposed on Gross for trying to set up illegal Internet connections on the island, according to Cuban state media reports.
Gross, 62, was jailed in December 2009, when he was working as a subcontractor on a U.S. Agency for International Development project aimed at spreading democracy. His actions were deemed illegal by Cuban authorities.
Gross says he was trying to help connect the Jewish community to the Internet and was not a threat to the government.
The case plunged U.S.-Cuba relations to a new low after signs of thawing when President Barack Obama took office. The State Department has said no progress will be made until Gross is released.
Former President Jimmy Carter visited Cuba earlier this year and tried to secure the aid worker's release on humanitarian grounds, arguing that Gross' mother and daughter are battling cancer. But he went home empty-handed.
U.S. officials say they hope the Cuban government will consider releasing Gross early now that the courts have had their say.
The Gross family statement expressed hope that Richardson and Cuban authorities "are able to find common ground that will allow us to be reunited as a family before the Jewish High Holy Days," which begin on September 28 this year with the Jewish New Year, Rosh Hashanah.