Cubans got from United States only about 15,000 of the 20,000 emigrant visas it had agreed to issue.
"It has been impossible this year to maintain the rhythm of work" of past years because of insufficient personnel, said Sean Murphy, consul general at the U.S. Interests Section in Havana.
He said Cuban authorities have not allowed the American mission to fill 11 job openings, all typically held by Cuban citizens, on the section's 45-member binational staff.
Murphy said it is the first time since the two countries signed migration accords in 1995 that the United States has failed to meet the 20,000-visa quota outlined in that agreement.
Havana filed a formal protest in August after the U.S. State Department acknowledged it would not meet the quota. It accused Washington of violating accords aimed at ensuring safe and orderly migration, while U.S. officials blamed Cuban restrictions for the problem.
Cuban authorities in the past have maintained that the U.S. government has the staffing needed to meet the quota and suggested that any unfilled positions were not for people involved with visa processing.
Under migration accords, the United States agreed to grant at least 20,000 visas annually to Cubans wanting to live in the U.S. in an effort to prevent a repeat of the 1994 migration crisis that saw more than 30,000 islanders take to the sea on makeshift rafts bound for South Florida.
During a briefing with international reporters, Murphy also said that the U.S. this year suspended its processing of Cuban applicants for U.S. immigrant visas chosen during several visa lotteries the American mission held in the late 1990s.
Known as the "bombo," the lottery was aimed at giving those Cubans without relatives in the U.S. a chance to emigrate. Cubans with family in America can be sponsored by relatives, making it easier to obtain U.S. emigrant visas.
As for illegal immigration, Murphy said 2,868 Cubans were intercepted at sea in the Florida Straits during the fiscal year that just ended, up slightly from the 2,810 intercepted at sea in the previous 12-month period.
He said most of those picked up were returned to their homeland under the so-called wet-foot/dry-foot policy that calls for most Cubans intercepted at sea to be repatriated while those who reach American shores may stay and seek U.S. residency.
But far more who undertook the risky journey escaped intervention at sea.
Murphy said 7,693 Cubans set off across the Florida Straits during the past fiscal year, up somewhat from the 7,088 who tried the journey during the previous 12 months.
While allowing that "the increase is not great," Murphy said the larger number of attempts could be related to milder weather at sea, as well as "a lack of hope" among Cubans. He said that about 70 percent of those making the sea journey are transported in fast boats by migrant smugglers, with the other 30 percent making the trip on their own in more rustic craft.
In a new trend, far more Cubans - about 10,000 a year - are now emigrating to the United States by passing through Mexico and traveling north to the U.S. border, Murphy said.