A senior Obama administration official says Cuba has released American Alan Gross, who has been imprisoned for five years as part of an agreement that includes the release of three Cubans jailed in the United States. 

Gross arrived in Andrews Air Force base outside of Washington, D.C. Wednesday morning. 

"Mr. Gross was released on humanitarian grounds by the Cuban government at the request of the United States," the senior U.S. official said. 

After news of release broke, American officials said that U.S. and Cuba will start talks to normalize full diplomatic relations as part of the most significant shift in U.S. policy toward the communist island in decades.

Officials say the U.S. is also looking to open an embassy in Havana in the coming months. The moves are part of an agreement between the U.S. and Cuba that also includes the release of American Alan Gross and three Cubans jailed in Florida for spying.

Sen. Marco Rubio, R-Florida, said the agreement includes normalizing banking and trade ties with Cuba.

Obama administration officials have considered Gross' imprisonment an impediment to improving relations with Cuba, but the surprise deal could help clear the way for broader discussions on strengthening ties and perhaps ending the decades-long U.S. economic embargo against its long-time communist foe.

Obama was to announce Gross' release later Wednesday, according to the officials, who insisted on anonymity because they were not authorized to discuss the matter by  name ahead of the president. Cuban President Raul Castro also said he would address his nation at noon to talk about Gross.

Gross was detained in December 2009 while working to set up Internet access as a subcontractor for the U.S. government's U.S. Agency for International Development, which does work promoting democracy in the communist country. It was his fifth trip to Cuba to work with Jewish communities on setting up Internet access that bypassed local censorship.

Cuba considers USAID's programs illegal attempts by the U.S. to undermine its government, and Gross was tried and sentenced to 15 years in prison.

The three Cubans released in exchange for Gross are part of the so-called Cuban Five -- a group of men who were part of the "Wasp Network" sent by Cuba's then-President Fidel Castro to spy in South Florida. The men, who are hailed as heroes in Cuba, were convicted in 2001 in Miami on charges including conspiracy and failure to register as foreign agents in the U.S.

Two of the Cuban Five were previously released after finishing their sentences.

In a statement marking the fifth anniversary of Gross' detention earlier this month, Obama hinted that his release could lead to a thaw in relations with Cuba.

"The Cuban Government's release of Alan on humanitarian grounds would remove an impediment to more constructive relations between the United States and Cuba," Obama said in a statement.

Based on reporting by the Associated Press.